feat(specify): add spec-production entry path; split brainstorm

Add `specify` as a third co-equal entry path into the dev cycle: it
produces an approved spec from already-settled sources (an exhaustive
issue, a long in-context design discussion, or a design brainstorm just
ratified) with review but no interview. This is the producing half of a
deliberate deciding/producing split — `brainstorm` shrinks to optional
discovery, `specify` becomes the sole spec-production gate before
`planner`, mirroring the RED->GREEN split that keeps tdd/debug honest.

What moved:
- brainstorm/SKILL.md: stripped of the hard-gate, the acceptance
  criterion, write-spec, self-review, grounding-check, user-review, and
  planner-handoff steps; terminal state is now handing a ratified design
  narrative to specify. Steps renumbered 1-5 (production steps left).
- specify/SKILL.md (new): the production core, with a precondition gate
  (Step 1.5) that bounces to brainstorm the moment the sources do not
  resolve a load-bearing decision — the same discipline tdd uses.
- The grounding-check agent moved brainstorm/agents/ -> specify/agents/
  (no-orphan-agents: it lives under its dispatcher), refs repointed.
- boss/SKILL.md: Entry-path reflection is now three-way (tdd / specify /
  brainstorm). specify dispatches autonomously (bounded, no interview)
  and pauses at its user-review gate; only a fresh brainstorm cycle
  stays a pre-dispatch bounce-back.
- pipeline.md, README, profile-schema, the profile template, and the
  migration layout updated so every pipeline rendering agrees; specify
  is a CORE node (not opt-in, unlike tdd) carrying gates: [planner].

Design alternative rejected: parallel sibling skills sharing a
docs/spec-production.md (extract-to-doc). Chosen extract-and-chain
instead — the shared surface is ~70%, so a shared doc would either
become the skill body or drift; chaining keeps one executed home for the
gates.

Verification (prose repo, no test suite): the spec's internal-
consistency grep suite (no two-path drift, no direct brainstorm->planner
edge, specify referenced in every rendering, grounding-check single home
under specify, specify structural completeness) all green. Orchestrator
inspection additionally fixed two dead step-refs the plan under-scoped
(a "(Step 4)" lift-validation pointer and a "Skipping Step 7
self-review" red flag, both pointing at steps brainstorm no longer has)
and corrected six pre-existing brainstorm->planner renderings in
pipeline.md and tdd that predated this cycle.

Known follow-ups (non-blocking): the committed spec writes
`skills/specify/` in places (typo; skill dirs are repo-top-level) — to
be corrected separately. The grounding-check hard-gate was degenerate
for this very cycle (this repo has no profile and no test suite); the
skip is documented in the spec and the session.

docs/migration.md

@@ -25,6 +25,8 @@ seven skills follow once the pattern is approved.
 ├── boss/                          (pilot: landed)
 │   └── SKILL.md
 ├── brainstorm/
+│   └── SKILL.md
+├── specify/
 │   ├── SKILL.md
 │   └── agents/
 │       └── grounding-check.md

docs/pipeline.md

@@ -4,10 +4,11 @@
 [new cycle]               [test-specifiable feature]      [bug observed]
        |                            |                            |
        v                            v                            v
- brainstorm  ->  plan  ->  implement                          debug -> implement (mini)
-       ^                            |
-       |                           tdd -> implement (mini)
-       +----(design fork)----------/   (RED executable-spec -> GREEN, like a bug fix)
+ brainstorm  ->  specify  ->  plan  ->  implement             debug -> implement (mini)
+       ^            ^               |
+       |            |              tdd -> implement (mini)
+       |       specify -> plan  (design settled in sources)
+       +----(design fork)----------/   (specify/tdd bounce here; RED executable-spec -> GREEN)
        (per iteration loop)
                   |
        [cycle close — a loop step, not a milestone close]
@@ -37,7 +38,7 @@
 These are two distinct axes, and conflating them is a bug.
 
 - A **cycle** is one round in the pipeline graph above
-  (`brainstorm → planner → implement → audit → [fieldtest]`).
+  (`brainstorm → specify → planner → implement → audit → [fieldtest]`).
   A cycle close is an internal loop step.
 - A **milestone** is a tracker container (Gitea milestone,
   GitHub milestone, Linear project — whatever the project's
@@ -85,9 +86,23 @@ close`); no skill performs it automatically.
 
 ### brainstorm
 
-Hard-gate before plan. Gathers requirements, explores 2-3
-approaches with trade-offs, presents a sectioned design with
-user approval, writes the spec to the configured `spec_dir`.
+Optional discovery front-end. Gathers requirements, explores 2-3
+approaches with trade-offs, presents a sectioned design with user
+approval, then hands the ratified design to `specify` (it writes no
+spec itself). Skipped when the design is already settled in the
+sources — that work enters through `specify` directly.
+
+### specify
+
+Hard-gate before plan — the spec-production core and the carrier of the
+"no plan without an approved spec" invariant. Takes a settled design
+(directly from sources, or a ratified design handed over by
+`brainstorm`), applies the feature-acceptance criterion, writes the
+spec to the configured `spec_dir`, runs the parse-every-block and
+`grounding-check` gates, and takes user sign-off — with review but no
+interview. Bounces to `brainstorm` the moment the sources do not
+resolve a load-bearing design decision. A core node, not opt-in
+(unlike `tdd`).
 
 ### planner
 
@@ -119,7 +134,7 @@ the GREEN side to the implement skill in mini mode.
 
 ### tdd
 
-Opt-in alternative to the `brainstorm → planner` design entry,
+Opt-in alternative to the `brainstorm → specify → planner` design entry,
 for work whose desired behaviour is test-specifiable — expressible
 as one failing test. RED-first: the `tdd-author` agent turns a
 description or issue into a single minimal, autonomous RED
@@ -172,7 +187,11 @@ Reviewer agents have role-specific states:
 Skipping is codified per skill, not ad hoc. Each `SKILL.md`
 documents what the skill skips and under what conditions:
 
-- `brainstorm` is never skipped at cycle start.
+- `specify` is never skipped at cycle start — it is the spec-production
+  gate before `planner`. `brainstorm` is the *optional* discovery stage
+  before it: skipped when the design is already settled in the sources
+  (the work enters through `specify` directly), run when a load-bearing
+  decision is still open.
 - `planner` is never skipped at iteration start, except for
   the bug-driven `debug → implement (mini)` side path.
 - `implement` is the iteration body; not skippable.

docs/profile-schema.md

@@ -9,7 +9,7 @@ lowercase snake_case. Lists are YAML sequences.
 
 | Key                 | Type   | Default                | Description |
 |---------------------|--------|------------------------|-------------|
-| `spec_dir`          | string | `docs/specs`           | Where the brainstorm skill writes specs. |
+| `spec_dir`          | string | `docs/specs`           | Where the specify skill writes specs. |
 | `plan_dir`          | string | `docs/plans`           | Where the planner skill writes plans. |
 | `glossary`          | string | (unset)                | Canonical-nomenclature file (optional). If set, it is standing reading for every role — no separate `standing_reading.always` entry is needed; unset is a documented no-op. See `glossary-convention.md`. |
 | `design_ledger`     | string | `docs/design/INDEX.md` | Canonical specification index (optional — projects without a design ledger can omit). |
@@ -188,7 +188,10 @@ Per-phase configuration. Each phase has its own sub-map.
 ```yaml
 pipeline:
   brainstorm:
-    gates: [planner]              # planner cannot start until this has run
+    gates: [specify]              # optional discovery; hands ratified design to specify
+    optional: true                # skipped when the design is settled in the sources
+  specify:
+    gates: [planner]              # core node — planner cannot start until the spec is approved
   planner:
     gates: [implement]
   implement: {}                   # standard
@@ -207,6 +210,7 @@ pipeline:
   debug:
     trigger: bug                  # observable misbehaviour
     red_first: true               # RED test before any fix
+  # specify above is a CORE node (always present); tdd below is opt-in.
   tdd:                            # opt-in: omit the key to disable the entry path
     trigger: test_specifiable_feature  # behaviour expressible as one failing test
     red_first: true               # RED executable-spec before any implementation
@@ -217,8 +221,12 @@ pipeline:
 
 Phases not listed are disabled for the project. A project that
 does not want a `fieldtest` phase simply omits the key. `tdd` is
-opt-in the same way: a profile that omits it keeps
-`brainstorm → planner` as the only design entry path.
+opt-in the same way. `specify`, by contrast, is a **core** node — it
+is the spec-production gate before `planner` on every design path,
+reachable directly from settled sources or via the optional
+`brainstorm` discovery stage. `tdd` opt-in only adds the
+test-specifiable bypass; with `tdd` omitted, the design entry paths
+are `brainstorm → specify → planner` and `specify → planner`.
 
 ## Example: minimal profile
 
@@ -247,7 +255,8 @@ git:
     close_marker: "closes #N"
 
 pipeline:
-  brainstorm: { gates: [planner] }
+  brainstorm: { gates: [specify], optional: true }
+  specify:    { gates: [planner] }
   planner:    { gates: [implement] }
   implement:  {}
   audit:      { mandatory_at: cycle_close }