fix(tool-fs): CRLF-safe write diff, opaque meta, doc sync

Address the applied-hunk-diffs review:

- CRLF write overwrite emitted bogus every-line-changed hunks: write's
  `before` was LF-normalized but `after` kept the raw model content, so a
  CRLF rewrite of an LF file diffed every line. Normalize write's `after`
  to LF so both sides share the diff basis (edit already did). Regression
  test proves it fails on the raw-after path.
- The tool-private `meta` payload is now typed `unknown` (opaque) at every
  seam instead of `JsonValue`. This drops the `dsh-tools -> dsh-session`
  package edge that existed only to name the type, and removes the
  `FileDiff` index signature that had been widening the type solely for
  JsonValue-assignability. Serializability is still enforced at runtime by
  `Session.append`'s isJsonValue check, which was always the real guard.
- Sync the docs the new result/meta surface left stale: ToolResultView's
  diff card + ToolExecutionResult.meta in tools.md/session.md type-equiv
  blocks, the acp/tools READMEs, and the adding-a-tool cookbook; regenerate
  the cordis catalog and module graph.

docs/cookbook/adding-a-tool.md

@@ -36,6 +36,7 @@ Registration is effect-based: disposing the plugin fiber unregisters the tool (w
 - **Args are validated for you.** `defineTool` validates the model-generated `arguments` against the `SchemaSpec` before `execute` runs (type, required keys, enum membership, nested objects/arrays — [runtime arg validation](../rfc/implemented/architecture/2026-06-11-runtime-arg-validation.md)), so inside `execute` the args already match `InferArgs`. You still hand-check value constraints the DSL can't express (non-empty strings, positive numbers, cross-field rules); throw a descriptive Error for those. Raw JSON-Schema tools registered directly (MCP) are NOT validated by the harness — they validate their own input.
 - **Throwing means isError.** The registry catches anything `execute()` throws and returns `{isError: true}` to the model. Use that for infrastructure failures (bad input, spawn errors, aborts) — but REPORT domain failures in the result text instead (e.g. tool-bash returns `[exit code: 9]` with `isError: false`: the model decides what a failing command means).
 - **Honor `exec.signal`.** Cancel in-flight work when it fires.
+- **Attach durable card data with `meta` (optional).** `execute` may return `{ content, meta }` instead of a bare `ContentBlock[]` — `meta` is a JSON-serializable payload the core treats as opaque, persisted on the `tool/result` event and handed back to your `presentResult` (so a card that needs more than `args`, like `write`/`edit`'s applied-hunk diff, survives a session replay). Keep UI-only data here, never in the model-facing `content`.
 - **Use `exec.agent` for async notifications.** `agent.inject(content, {source: {kind: 'plugin', plugin: '<name>'}})` appends durable context the NEXT model request sees — it is not a wake-up (an idle agent stays idle). Guard against disposed agents (try/catch).
 
 ## Long-running work
@@ -58,7 +59,7 @@ Both methods return a **`card`-tagged render intent** — pick the card kind tha
   - `{ card: 'generic', title, kind?, rawInput?, content?, locations? }` — the default. Set `kind` for an icon (`read`/`search`/…); set `locations: [{ path, line? }]` for any file your tool touches so a capable editor follows along / jumps to it.
   - `{ card: 'terminal', title, description?, cwd? }` — your call IS a shell command. `title` is the command, `description` renders above the terminal card. (tool-bash.)
   - `{ card: 'diff', title, diffs, locations? }` — your call creates or modifies a file. `diffs: [{ path, oldText, newText }]` (`oldText: null` for a new file) renders as an inline diff card. (tool-fs `write`/`edit`.)
-- `presentResult(args, { content, isError })` → a `ToolResultView` (the COMPLETED card): `{ card: 'generic', title?, content? }` or `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the run's captured output + exit — the bridge shows an exit pill and derives a fenced ` ```console ` fallback for editors without the terminal capability).
+- `presentResult(args, { content, isError, meta? })` → a `ToolResultView` (the COMPLETED card): `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the run's captured output + exit — the bridge shows an exit pill and derives a fenced ` ```console ` fallback for editors without the terminal capability), or `{ card: 'diff', title?, diffs }` (the APPLIED hunks of a completed file mutation, computed from the before/after content — `write`/`edit` attach the hunks via the `meta` channel and read them back here). `result.meta` is your tool's own optional presentation payload, attached from `execute` (see below) and persisted so a replay reproduces the card.
 
 Hard rules (they bite if broken):
 

docs/cordis-catalog/events-and-services.md

@@ -337,7 +337,7 @@ A tool was registered or unregistered (the available tool set changed).
 'tools/change'(): void
 ```
 
-Source: [`packages/core/tools/src/index.ts:49`](../../packages/core/tools/src/index.ts)
+Source: [`packages/core/tools/src/index.ts:48`](../../packages/core/tools/src/index.ts)
 
 #### `tools/execute` — waterfall
 
@@ -349,7 +349,7 @@ Waterfall around every tool execution — the single seam where sandbox, permiss
 
 Types: [ToolExecution](../core-data-structures/tools.md) · [ToolExecutionResult](../core-data-structures/tools.md)
 
-Source: [`packages/core/tools/src/index.ts:44`](../../packages/core/tools/src/index.ts)
+Source: [`packages/core/tools/src/index.ts:43`](../../packages/core/tools/src/index.ts)
 
 ## Services
 
@@ -547,7 +547,7 @@ async execute(exec: ToolExecution): Promise<ToolExecutionResult>
 
 Types: [ToolDefinition](../core-data-structures/tools.md) · [ToolExecution](../core-data-structures/tools.md) · [ToolExecutionResult](../core-data-structures/tools.md)
 
-Source: [`packages/core/tools/src/index.ts:370`](../../packages/core/tools/src/index.ts)
+Source: [`packages/core/tools/src/index.ts:363`](../../packages/core/tools/src/index.ts)
 
 ## Inherited tier (cordis core + loader/hmr/timer)
 

docs/core-data-structures/session.md

@@ -32,7 +32,7 @@ interface SessionEventMap {
    */
   'assistant/message': { turn: number; step: number; content: ContentBlock[]; usage?: TokenUsage }
   'tool/call': { turn: number; step: number; callId: CallId; name: string; arguments: string }
-  'tool/result': { turn: number; step: number; callId: CallId; content: ContentBlock[]; isError: boolean; error?: { name: string; code: string }; meta?: JsonValue }
+  'tool/result': { turn: number; step: number; callId: CallId; content: ContentBlock[]; isError: boolean; error?: { name: string; code: string }; meta?: unknown }
   /** Steering content injected between steps of a running turn. */
   'steering/message': { turn: number; content: ContentBlock[]; source: MessageSource }
   /**

docs/core-data-structures/tools.md

@@ -106,7 +106,7 @@ interface ToolExecutionResult {
    * {@link ToolResult} for `presentResult`. Opaque {@link JsonValue}; absent when
    * the tool attached none or the call failed.
    */
-  meta?: JsonValue
+  meta?: unknown
 }
 ```
 
@@ -117,7 +117,7 @@ A waterfall listener receives `(exec, next)`: call `next()` to proceed (possibly
 How a tool wants its call shown in a UI (an editor tool-call card, a CLI log line), provider-neutral so a tool describes itself without depending on any client protocol. `presentCall`/`presentResult` return a **`card`-tagged render intent** — a discriminated union a UI bridge switches on:
 
 - `ToolCallView` (pending): `{ card: 'generic', title, kind?, rawInput?, content?, locations? }` (the default card; `locations` is `{ path, line? }[]` files the call reads/modifies, for editor follow-along), `{ card: 'terminal', title, description?, cwd? }` (a shell command → a terminal card), or `{ card: 'diff', title, diffs, locations? }` (a file create/modify → an inline diff card; `diffs` is `{ path, oldText, newText }[]`, `oldText: null` for a new file).
-- `ToolResultView` (completed): `{ card: 'generic', title?, content? }` or `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the captured run output + exit; a capable UI shows an exit-status pill, an incapable one gets a fenced ` ```console ` fallback the bridge derives from `output`).
+- `ToolResultView` (completed): `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the captured run output + exit; a capable UI shows an exit-status pill, an incapable one gets a fenced ` ```console ` fallback the bridge derives from `output`), or `{ card: 'diff', title?, diffs }` (a completed file mutation → the APPLIED hunks with context lines, one entry per changed site, computed from the before/after file content — distinct from the call-time whole-snippet `diff`, which it supersedes).
 
 `ToolCallKind` (`'read' | 'edit' | 'delete' | 'move' | 'search' | 'execute' | 'fetch' | 'other'`) picks an icon on a generic card. `FileLocation` (`{ path, line? }`) and `FileDiff` (`{ path, oldText, newText }`) are the shared file-card vocabulary. The design is pinned in [the render-intent-union RFC](../rfc/implemented/architecture/2026-07-02-tool-render-intent-union.md); the ACP bridge maps a `diff` card to a `{ type: 'diff' }` content block, a `terminal` card to the `_meta` terminal convention, and relativizes a file card's title against the session cwd.
 

docs/module-graph.md

@@ -40,7 +40,6 @@ graph TD
   session-persistence-sqlite --> session-persistence
   tools --> agent
   tools --> llm
-  tools --> session
   tools --> system-prompt
   ui-stdio --> agent
   ui-stdio --> llm
@@ -130,7 +129,7 @@ graph TD
 | `invariants` | `agent`, `llm`, `session` |
 | `session-persistence-jsonl` | `session`, `session-persistence` |
 | `session-persistence-sqlite` | `session`, `session-persistence` |
-| `tools` | `agent`, `llm`, `session`, `system-prompt` |
+| `tools` | `agent`, `llm`, `system-prompt` |
 | `ui-stdio` | `agent`, `llm`, `session` |
 | `acp` | `agent`, `llm`, `session`, `session-persistence`, `tools` |
 | `agent-loop` | `agent`, `llm`, `session`, `session-persistence`, `system-prompt`, `tools` |

docs/rfc/implemented/architecture/2026-07-02-result-time-applied-hunk-diffs.md

@@ -16,13 +16,13 @@ Add a **persisted, tool-private presentation channel** so a tool's `execute` can
 
 ### 1. A `meta` channel on the tool result (core)
 
-`ToolDefinition.execute` may now return either its model-facing `ContentBlock[]` (unchanged, the common case) OR `{ content: ContentBlock[]; meta?: JsonValue }`:
+`ToolDefinition.execute` may now return either its model-facing `ContentBlock[]` (unchanged, the common case) OR `{ content: ContentBlock[]; meta?: unknown }`:
 
 ```ts ignore-check
-type ToolExecuteReturn = ContentBlock[] | { content: ContentBlock[]; meta?: JsonValue }
+type ToolExecuteReturn = ContentBlock[] | { content: ContentBlock[]; meta?: unknown }
 ```
 
-`meta` is an opaque, JSON-serializable payload the core never interprets. The registry threads it onto the `tool/result` **session event** (`{ …, meta?: JsonValue }`), so it is persisted with the log; on replay the same `meta` is read back and handed to `presentResult` via a widened `ToolResult` (`{ content, isError, meta? }`). Because the payload lives in the event log, the diff reproduces on session reload / snapshot replay **for free** — the event-sourcing guarantee, not a re-computation. `JsonValue` is exported from `dsh-session` (paired with the existing `isJsonValue` predicate that already gates every event's serializability at `append`).
+`meta` is an opaque payload the core never interprets — typed `unknown` at every seam (the tool that produced it owns and narrows its shape). It MUST be JSON-serializable: the registry threads it onto the `tool/result` **session event**, and `Session.append` runtime-validates all event data with the existing `isJsonValue` predicate, so a non-serializable `meta` is rejected at the source. On replay the same `meta` is read back and handed to `presentResult` via a widened `ToolResult` (`{ content, isError, meta? }`). Because the payload lives in the event log, the diff reproduces on session reload / snapshot replay **for free** — the event-sourcing guarantee, not a re-computation. Typing `meta` as `unknown` (rather than a shared serializable-value type) keeps the tools core free of a dependency it would otherwise take just to name the type, and the runtime `isJsonValue` gate — not the static type — is what actually enforces serializability.
 
 This is the general shape ("a tool attaches durable result presentation"), not an fs-specific one — any tool can use it.
 
@@ -39,7 +39,7 @@ Per the [capability-seam split](2026-06-13-capability-seams.md), the storage bac
 
 ### The diff algorithm — a third-party runtime dependency over vendoring
 
-Computing hunks-with-context is a solved problem with sharp edge cases (grouping, context coalescing, the trailing-newline marker). Rather than hand-roll it, `dsh-tool-fs` takes a runtime dependency on the npm [`diff`](https://www.npmjs.com/package/diff) package (v9, ships its own types) and uses its `structuredPatch`. The repo's default is to vendor Cordis-framework source, but that policy is about the *framework*; a leaf tool package taking a small, well-known, self-typed utility dependency is the same shape as `dsh-acp` depending on `@agentclientprotocol/sdk`. Vendoring a diff algorithm would be re-implementing a battle-tested one for no benefit — the [pre-release "foundation over blast radius"](../../../../AGENTS.md) reasoning does not argue for re-deriving standard algorithms. The dependency is pinned and its output is normalized in one small module (`packages/fs/tool-fs/src/diff.ts`).
+Computing hunks-with-context is a solved problem with sharp edge cases (grouping, context coalescing, the trailing-newline marker). Rather than hand-roll it, `dsh-tool-fs` takes a runtime dependency on the npm [`diff`](https://www.npmjs.com/package/diff) package (a `^9.0.0` range, exact-pinned by the lockfile; it ships its own types) and uses its `structuredPatch`. The repo's default is to vendor Cordis-framework source, but that policy is about the *framework*; a leaf tool package taking a small, well-known, self-typed utility dependency is the same shape as `dsh-acp` depending on `@agentclientprotocol/sdk`. Vendoring a diff algorithm would be re-implementing a battle-tested one for no benefit — the [pre-release "foundation over blast radius"](../../../../AGENTS.md) reasoning does not argue for re-deriving standard algorithms. The dependency's output is normalized in one small module (`packages/fs/tool-fs/src/diff.ts`).
 
 ## Non-goals