Fix doc cross-links for the hierarchy; add package-path + shape gates

Merge brought in the RFC-classification reorg and two new doc gates;
rewrite every drifted packages/<name> cross-link (Markdown link targets,
moved-README relative depths, and .ts comment paths) to the grouped paths.

Add two doc-sync/hygiene gates so the manual checks this restructure
needed become automated:
- verify-package-paths.ts: flags a packages/<path> reference (in Markdown
  or a .ts comment/string) that does not resolve AND names a real package
  in a segment — i.e. a stale path to a MOVED package. A path naming a
  non-existent package (a forward-looking proposal) is left alone, so it
  applies uniformly across proposed/implemented/rejected.
- check-workspace-constraints: assert the packages/<group>/<pkg> depth-2
  shape (group dirs carry no package.json; no flat or over-nested
  packages). Group names stay open; only the shape is fixed.

packages/session-persistence/session-persistence-jsonl/README.md

@@ -23,7 +23,7 @@ The JSONL durable session-persistence backend — a concrete `SessionPersistence
 
 - **Lazy materialization.** `create(meta)` writes nothing; the `.jsonl` (header + first batch) is written atomically (temp-write + `fsync` + rename) on the first `append`. A created-but-never-appended session leaves nothing on disk and is absent from `has`/`list`.
 - **Append-only.** Committed events (at or below a flushed `turn/end`) are never rewritten. Subsequent appends are line appends at EOF + `fsync`.
-- **Crash recovery — close, don't truncate.** A crash can leave a log whose final turn never closed (real events after the last `turn/end`). `load` PRESERVES those events (a turn can be huge — they are real work) and closes the orphaned turn by durably appending synthetic boundary events: an error `tool/result` for every `tool-call` the crash left unanswered (the loop logs the assistant message before running the tools, so a mid-tool crash leaves dangling calls — and `deriveMessages()` would replay an assistant tool-call with no result, which providers reject), then a `step/end` if a step was open, then `turn/end {kind:'interrupted'}`, returning a balanced log. Only a never-fully-written **torn tail fragment** (a final line with no newline / unparseable) is `ftruncate`d away before the closers are written. See [session persistence](../../docs/rfc/implemented/architecture/2026-06-14-session-persistence.md).
+- **Crash recovery — close, don't truncate.** A crash can leave a log whose final turn never closed (real events after the last `turn/end`). `load` PRESERVES those events (a turn can be huge — they are real work) and closes the orphaned turn by durably appending synthetic boundary events: an error `tool/result` for every `tool-call` the crash left unanswered (the loop logs the assistant message before running the tools, so a mid-tool crash leaves dangling calls — and `deriveMessages()` would replay an assistant tool-call with no result, which providers reject), then a `step/end` if a step was open, then `turn/end {kind:'interrupted'}`, returning a balanced log. Only a never-fully-written **torn tail fragment** (a final line with no newline / unparseable) is `ftruncate`d away before the closers are written. See [session persistence](../../../docs/rfc/implemented/architecture/2026-06-14-session-persistence.md).
 - **Contiguous-seq.** `load` rejects a mid-log parse error or `seq` gap (unloadable); `append` rejects a batch whose first `seq` does not continue the stored log, and rejects non-JSON-serializable `event.data` naming the offending event type.
 - **Format version.** Only v1 is supported; `load` rejects an unknown version. While the harness is unreleased a format change bumps the version and rejects non-current logs — there is no migration (no persisted user data to preserve).
 

packages/session-persistence/session-persistence-sqlite/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-session-persistence-sqlite
 
-A SQLite durable session-persistence backend — a second `SessionPersistence` implementation ([session persistence](../../docs/rfc/implemented/architecture/2026-06-14-session-persistence.md)), built to validate that the abstract seam and the shared `runPersistenceContract` suite are genuinely backend-agnostic. It satisfies the SAME contract as `dsh-session-persistence-jsonl` (append-only, contiguous-seq, lazy materialization, interrupted-turn close on load), expressed over `node:sqlite` rows instead of file bytes.
+A SQLite durable session-persistence backend — a second `SessionPersistence` implementation ([session persistence](../../../docs/rfc/implemented/architecture/2026-06-14-session-persistence.md)), built to validate that the abstract seam and the shared `runPersistenceContract` suite are genuinely backend-agnostic. It satisfies the SAME contract as `dsh-session-persistence-jsonl` (append-only, contiguous-seq, lazy materialization, interrupted-turn close on load), expressed over `node:sqlite` rows instead of file bytes.
 
 > **TODO:** this backend talks to `node:sqlite` directly. If a cordis database service (`cordis/db` / a `@cordisjs` SQL driver plugin) is adopted, route through that instead of holding a raw `DatabaseSync` here — the contract surface (`SessionPersistence`) would not change, only the storage driver.
 

packages/session-persistence/session-persistence/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-session-persistence
 
-The abstract durable session-persistence seam (`ctx.sessionPersistence`). Defines WHAT a persistence backend does — durably store, reload, and list sessions — without saying HOW. Mirrors the `dsh-bash` capability-seam template ([capability seams](../../docs/rfc/implemented/architecture/2026-06-13-capability-seams.md)): an abstract service here, a concrete implementation in a sibling package, consumers that inject the interface.
+The abstract durable session-persistence seam (`ctx.sessionPersistence`). Defines WHAT a persistence backend does — durably store, reload, and list sessions — without saying HOW. Mirrors the `dsh-bash` capability-seam template ([capability seams](../../../docs/rfc/implemented/architecture/2026-06-13-capability-seams.md)): an abstract service here, a concrete implementation in a sibling package, consumers that inject the interface.
 
 The persisted unit IS the existing `SessionEvent` (event-sourced model — the log is the single source of truth), so there is no parallel "persisted message" type. Metadata that is NOT replayable conversation state (format version, cwd, lineage) travels separately as `SessionHeader`, owned by `dsh-session` and re-exported here.
 
@@ -39,7 +39,7 @@ The `PersistenceBackend<TornMarker>` hooks (the only seam between the coordinato
 | `deleteStored(id)` / `list()` | Remove a stored artifact / list all stored metadata. |
 | `close?()` | Optional lifecycle teardown (e.g. close a db handle), awaited after the dispose drain. |
 
-The `tornMarker` is fully OPAQUE: the coordinator only tests `!== undefined` and round-trips it to `commitRepair`, never inspecting its value (the JSONL backend uses the byte offset to truncate to, the SQLite backend the seq to delete from). The public `SessionPersistence` service shape is unchanged, so a third-party backend MAY still implement the abstract service directly without the coordinator. See [the write-coordinator RFC](../../docs/rfc/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md).
+The `tornMarker` is fully OPAQUE: the coordinator only tests `!== undefined` and round-trips it to `commitRepair`, never inspecting its value (the JSONL backend uses the byte offset to truncate to, the SQLite backend the seq to delete from). The public `SessionPersistence` service shape is unchanged, so a third-party backend MAY still implement the abstract service directly without the coordinator. See [the write-coordinator RFC](../../../docs/rfc/implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md).
 
 ## Testing backends