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/bash/tool-bash/README.md

@@ -34,7 +34,7 @@ The owning agent's session token (`session.header.id`) is stamped onto the task
 
 ## UI presentation
 
-These tools own how their calls render in a UI (an editor's tool-call card) via the `dsh-tools` `presentCall`/`presentResult` seam — a UI never special-cases tool names. For `bash`: the **title** is the exact `command` ("ls -la src") and `kind` is `execute` (terminal/run treatment), matching the reference ACP adapters (claude-agent-acp, codex-acp), which both use the bare command as an execute tool's title. The command is ALSO the **rawInput** for non-terminal UIs that render it (an execute-kind card hides rawInput — Zed shows it only for non-terminal tools — so the command must BE the title to be seen). The model-written `description` rides as a **content** text block shown ABOVE the card. (claude-agent-acp DROPS the description in terminal mode and shows only the card; surfacing it as a content block is a deliberate divergence — we keep the human summary visible alongside the card.) The completed output is wrapped in a fenced ` ```console ` block as the no-terminal-capability fallback — a UI-only affordance, so the model-facing result text stays unfenced. A FOREGROUND `bash` run also flags itself as a **terminal** (the neutral `terminal` field: `presentCall` sets a `cwd` from the model `workdir` when given — absolute as-is, relative for the UI bridge to resolve against the session cwd — else leaves it for the bridge to fill from the session cwd; `presentResult` carries the raw output plus the parsed `exitCode`/`signal`) so a capable client (Zed) renders a terminal card with an exit-status pill instead of the text block — see `packages/acp` ("Terminal card"). A `run_in_background` call is NOT a terminal (it returns a task id immediately and never streams a terminal — poll with `bash_output`), and an `isError` result (spawn failure / abort) carries no exit pill (there is no real process exit); both render as the ordinary execute card / fenced text. `bash_output`/`bash_kill` present a task-scoped title ("Read output from background task bash-3" / "Kill background task bash-3") with the task id as rawInput. These methods are pure/display-only (they also run on `session/load` replay), and a malformed/older logged arg shape falls back to a generic presentation rather than throwing. See `packages/tools` ("Tool-owned UI presentation") and `packages/acp` ("Terminal card" / "Tool-call presentation").
+These tools own how their calls render in a UI (an editor's tool-call card) via the `dsh-tools` `presentCall`/`presentResult` seam — a UI never special-cases tool names. For `bash`: the **title** is the exact `command` ("ls -la src") and `kind` is `execute` (terminal/run treatment), matching the reference ACP adapters (claude-agent-acp, codex-acp), which both use the bare command as an execute tool's title. The command is ALSO the **rawInput** for non-terminal UIs that render it (an execute-kind card hides rawInput — Zed shows it only for non-terminal tools — so the command must BE the title to be seen). The model-written `description` rides as a **content** text block shown ABOVE the card. (claude-agent-acp DROPS the description in terminal mode and shows only the card; surfacing it as a content block is a deliberate divergence — we keep the human summary visible alongside the card.) The completed output is wrapped in a fenced ` ```console ` block as the no-terminal-capability fallback — a UI-only affordance, so the model-facing result text stays unfenced. A FOREGROUND `bash` run also flags itself as a **terminal** (the neutral `terminal` field: `presentCall` sets a `cwd` from the model `workdir` when given — absolute as-is, relative for the UI bridge to resolve against the session cwd — else leaves it for the bridge to fill from the session cwd; `presentResult` carries the raw output plus the parsed `exitCode`/`signal`) so a capable client (Zed) renders a terminal card with an exit-status pill instead of the text block — see `packages/ui/acp` ("Terminal card"). A `run_in_background` call is NOT a terminal (it returns a task id immediately and never streams a terminal — poll with `bash_output`), and an `isError` result (spawn failure / abort) carries no exit pill (there is no real process exit); both render as the ordinary execute card / fenced text. `bash_output`/`bash_kill` present a task-scoped title ("Read output from background task bash-3" / "Kill background task bash-3") with the task id as rawInput. These methods are pure/display-only (they also run on `session/load` replay), and a malformed/older logged arg shape falls back to a generic presentation rather than throwing. See `packages/core/tools` ("Tool-owned UI presentation") and `packages/ui/acp` ("Terminal card" / "Tool-call presentation").
 
 ## Background completion notices