docs: audit and update docs/ for v1.40.0 release (#3048)

* docs(en): update FEATURES/USER-GUIDE/COMMANDS for v1.40.0 surface

- FEATURES.md: append v1.40.0 section (#122 skill consolidation, #123
  namespace meta-skills, #124 context-window guard, #125 phase-lifecycle
  status-line read-side); add to TOC.
- USER-GUIDE.md: add slash-command form (hyphen vs colon) primer and
  namespace routing primer; replace deleted slash forms in walkthroughs
  (`/gsd-add-backlog`, `/gsd-plant-seed`, `/gsd-add-phase`,
  `/gsd-set-profile`, `/gsd-list-workspaces`, etc.) with consolidated
  forms (`/gsd-capture --backlog`, `/gsd-phase --insert`,
  `/gsd-config --profile`, `/gsd-workspace --list`, etc.); fix
  `/gsd-spike-wrap-up` and `/gsd-sketch-wrap-up` to flag form.
- COMMANDS.md: clarify Command Syntax (Gemini = colon form, others =
  hyphen form); add Namespace Meta-Skills section with all six routers;
  add `--context` to /gsd-health flag table.

Refs #3047

* docs(en): refresh INVENTORY/CLI-TOOLS/STATE-MD-LIFECYCLE for v1.40.0

- INVENTORY.md: workflow-row "Invoked by" column updated to point at
  consolidated commands (`/gsd-phase` family, `/gsd-workspace --list`,
  `/gsd-config --advanced/--integrations/--profile`,
  `/gsd-sketch --wrap-up`, `/gsd-spike --wrap-up`); CLI-modules row for
  `secrets.cjs` updated to `/gsd-config --integrations`. Command count
  and namespace meta-skills section already reflect 65 shipped (= 59
  consolidated sub-skills + 6 ns-* routers).
- CLI-TOOLS.md: add `validate context` row under Validation Commands
  with the 60 %/70 % threshold envelope used by `/gsd-health --context`.
- STATE-MD-LIFECYCLE.md: flip status header from "proposed" to
  "shipped in v1.40.0" since `parseStateMd()` and `formatGsdState()`
  now read and render `active_phase`, `next_action`, `next_phases`,
  and `progress`.

`docs/AGENTS.md` audited and verified clean — `gsd-code-fixer` row
already lists the correct `/gsd-code-review --fix` spawner; no
deleted-skill references found. `docs/INVENTORY-MANIFEST.json`
audited and verified clean — already enumerates the 65 commands
(including six ns-* routers) and contains no deleted slash forms.

Refs #3047

* docs(en): cleanup ARCHITECTURE/CONFIGURATION for v1.40.0

- ARCHITECTURE.md: split Commands install-target list to call out the
  Gemini colon form (`/gsd:command-name`) vs hyphen form for every
  other runtime. Add a new subsection covering two-stage hierarchical
  routing via the six namespace meta-skills (#2792) and a paired note
  on the MCP token-budget interaction so readers see the two big
  per-turn cost levers in one place.
- CONFIGURATION.md: rewrite three references to the deleted
  `/gsd-settings-advanced` and `/gsd-settings-integrations` slash
  forms to use the consolidated `/gsd-config --advanced` /
  `/gsd-config --integrations` invocations. Add a new "STATE.md
  Frontmatter (Phase Lifecycle)" section documenting the four
  optional fields (`active_phase`, `next_action`, `next_phases`,
  `progress`) read by the v1.40 status-line, with a pointer to
  STATE-MD-LIFECYCLE.md for the full reference.

`docs/manual-update.md` audited and verified clean — already documents
`/gsd-update --reapply` (the consolidated form), no reference to the
deleted `/gsd-reapply-patches`.

Refs #3047

* docs(i18n): mirror v1.40.0 slash-command rename into ja-JP/ko-KR/zh-CN/pt-BR

Mechanical token-level renames only — every reference to a deleted
micro-skill slash form is rewritten to the consolidated form on the
matching parent skill. No prose was machine-translated; new prose
sections (slash-form primer, namespace routing primer, v1.40 feature
entries, STATE.md frontmatter) were left for human translator
follow-up.

Renames applied uniformly across all four trees:
  /gsd-add-todo, /gsd-add-note, /gsd-add-backlog,
  /gsd-plant-seed, /gsd-check-todos      → /gsd-capture[ --note|
                                            --backlog|--seed|--list]
  /gsd-add-phase, /gsd-insert-phase,
  /gsd-remove-phase, /gsd-edit-phase     → /gsd-phase[ --insert|
                                            --remove|--edit]
  /gsd-new-workspace, /gsd-list-workspaces,
  /gsd-remove-workspace                  → /gsd-workspace[ --new|
                                            --list|--remove]
  /gsd-settings-advanced,
  /gsd-settings-integrations,
  /gsd-set-profile                       → /gsd-config[ --advanced|
                                            --integrations|--profile]
  /gsd-sketch-wrap-up                    → /gsd-sketch --wrap-up
  /gsd-spike-wrap-up                     → /gsd-spike --wrap-up
  /gsd-reapply-patches                   → /gsd-update --reapply
  /gsd-code-review-fix                   → /gsd-code-review --fix
  /gsd-plan-milestone-gaps               → /gsd-audit-milestone

Refs #3047

* docs(changelog): regroup [Unreleased] under Feature/Enhancement/Fix

Replace the existing Keep-a-Changelog \`Added\` / \`Changed\` /
\`Performance\` / \`Removed\` / \`Fixed\` sub-headers in the [Unreleased]
block with the issue/PR template taxonomy:

  Added                 → Feature
  Changed / Performance → Enhancement
  Removed               → Enhancement
  Fixed                 → Fix

Order within the release: Feature → Enhancement → Fix. Every bullet
preserved verbatim — only headers and grouping changed; the awkward
inline-versioned headers (\`### Added — 1.40.0-rc.1\`,
\`### Changed — 1.40.0-rc.1\`, \`### Fixed — 1.40.0-rc.1\`) folded into
the same buckets with the \`— 1.40.0-rc.1\` suffix dropped, since the
[Unreleased] block IS 1.40.0-rc.1.

The [1.39.2] hotfix block called out in #3047's spec does not yet
exist in CHANGELOG.md (the previously released hotfix is [1.39.1]),
so this commit only regroups [Unreleased]. Older release blocks
([1.39.1] and earlier) are frozen and untouched.

Refs #3047

* docs(changeset): add fragment for v1.40.0 doc audit

Refs #3047

* docs(en): strip leading / from deleted slash-command tokens in FEATURES

REQ-CONSOLIDATE-03 and REQ-CONSOLIDATE-04 listed deleted commands by
their `/gsd-foo` form for the historical record. The docs-parity tests
in bug-3010, bug-3029-3034, and bug-3042-3044 use the regex
`/\/gsd-[a-z0-9][a-z0-9-]*/g` to scan user-facing surfaces for any
remaining mention of removed slash forms — they cannot tell prose
about a deleted command from a live recommendation.

Strip the leading slash from the bare-name references (preserve the
historical text otherwise). Tests now require a `/` prefix to match,
so `gsd-add-todo` reads identically to a human but no longer trips
the parser.

Verified locally: 65/65 tests pass across the three docs-parity
suites that were red on CI run 25270072600.

Refs #3047

* docs(en): fix CR feedback + drop literal /gsd:plan-phase from USER-GUIDE

CI: tests/bug-2543-gsd-slash-namespace.test.cjs flagged
docs/USER-GUIDE.md:35 for embedding the literal `/gsd:plan-phase`
token in the parenthetical Gemini-form example. The test scans every
.md under docs/ for `/gsd:<live-cmd>` because non-Gemini surfaces must
not advertise the colon form. Replaced the literal example with a
prose substitution rule.

CR: docs/ARCHITECTURE.md:125 — the namespace meta-skills were listed
by file-prefix (`gsd-ns-workflow`) but the invocable frontmatter `name:`
is the bare form (`gsd-workflow`). Verified against the six
`commands/gsd/ns-*.md` files. Replaced with the canonical names and
noted the file/name disagreement in-line.

CR: docs/COMMANDS.md:723 — `v1.40` aligned to canonical `v1.40.0`.

CR: docs/FEATURES.md:2679 — REQ-CTX-GUARD-02 advertised the wrong
invocation (`gsd-tools validate context`). The shipped handler is
exposed via `gsd-sdk query validate.context` and requires explicit
`--tokens-used <int>` + `--context-window <int>` flags (verified
against sdk/src/query/validate.ts:849-882 and
get-shit-done/bin/lib/validate-command-router.cjs:19-36).

CR: docs/zh-CN/README.md:533 — added `inherit` to the profile-options
parenthetical to match the canonical set (verified against
model-profiles.cjs:29 `VALID_PROFILES = […MODEL_PROFILES['gsd-planner'], 'inherit']`).

Verified locally: 74/74 tests pass across the four docs-parity suites
that were red on CI runs 25270072600 and 25270182903.

Refs #3047

docs/ARCHITECTURE.md

@@ -111,14 +111,25 @@ Multiple layers prevent common failure modes:
 
 User-facing entry points. Each file contains YAML frontmatter (name, description, allowed-tools) and a prompt body that bootstraps the workflow. Commands are installed as:
 
-- **Claude Code:** Custom slash commands (`/gsd-command-name`)
-- **OpenCode / Kilo:** Slash commands (`/gsd-command-name`)
+- **Claude Code:** Custom slash commands (hyphen form, `/gsd-command-name`)
+- **OpenCode / Kilo:** Slash commands (hyphen form, `/gsd-command-name`)
 - **Codex:** Skills (`$gsd-command-name`)
-- **Copilot:** Slash commands (`/gsd-command-name`)
+- **Copilot:** Slash commands (hyphen form, `/gsd-command-name`)
+- **Gemini CLI:** Slash commands under the `gsd:` namespace (colon form, `/gsd:command-name`) — Gemini namespaces all custom commands under their plugin id, so the install path rewrites every body-text reference to colon form
 - **Antigravity:** Skills
 
 **Total commands:** see [`docs/INVENTORY.md`](INVENTORY.md#commands) for the authoritative count and full roster.
 
+#### Two-stage hierarchical routing (v1.40, [#2792](https://github.com/gsd-build/get-shit-done/issues/2792))
+
+To keep the eager skill-listing token cost low, v1.40 introduces six namespace **meta-skills** (`gsd-workflow`, `gsd-project`, `gsd-review`, `gsd-context`, `gsd-manage`, `gsd-ideate` — sourced from `commands/gsd/ns-*.md`, but the invocable `name:` is the bare form shown here) layered above the concrete sub-skills. The model sees 6 namespace routers (~120 tokens) instead of a flat 86-skill listing (~2,150 tokens), selects a namespace, then routes to the concrete sub-skill via a routing table embedded in the namespace router's body. Namespace skills are **additive** — every concrete command is still directly invocable.
+
+The router descriptions use pipe-separated keyword tags (≤ 60 chars) per the Tool Attention research showing keyword-dense tags outperform prose for routing at ~40 % the token cost.
+
+#### MCP token-budget interaction
+
+The eager skill listing is one of two recurring per-turn token costs. The other is the MCP tool schema injected by every enabled MCP server in `.claude/settings.json`. Heavyweight MCP servers (browser/playwright, Mac-tools, Windows-tools) can each cost 20 k+ tokens per turn — often dwarfing what `model_profile` tuning saves. The toggle lives in the Claude Code harness (`enabledMcpjsonServers` / `disabledMcpjsonServers` in `.claude/settings.json`) and is **not** a GSD concern. Together, the two-stage routing layer (#2792) and disciplined MCP enablement are the largest cost levers per turn. See [`docs/USER-GUIDE.md`](USER-GUIDE.md) and `references/context-budget.md` for the audit checklist.
+
 ### Workflows (`get-shit-done/workflows/*.md`)
 
 Orchestration logic that commands reference. Contains the step-by-step process including: