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/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)