refactor: drop dev-cycle-profile.yml for conventions + CLAUDE.md facts

The profile was never parsed — it was prose the skill bodies told the model to read, so most slots were dead, constant across every project, or fiction (the whole pipeline block, including the "tdd is opt-in" claim, was enforced by nothing).

Split it in two: constants become fixed conventions named directly by the skills (new docs/conventions.md), and the few genuinely per-project facts move to each project's CLAUDE.md under '## Skills plugin: project facts'. tdd/fieldtest/docwriter are now always available; the only behavioural toggle left is spec auto-sign.

Delete docs/profile-schema.md and templates/project-profile.yml; add docs/conventions.md and a project-facts section to templates/CLAUDE.md.fragment; rewrite all SKILL/agent prose and the pipeline/design/migration/README/INSTALL docs accordingly.

brainstorm/SKILL.md

@@ -19,7 +19,7 @@ to prevent.
 
 `brainstorm` does not write the spec. Its terminal state is handing the
 ratified design to `specify` (the spec-production core), which applies
-the acceptance criterion, writes the spec under `paths.spec_dir`, runs
+the acceptance criterion, writes the spec under `docs/specs`, runs
 the gates, and takes user sign-off. When the design is *already*
 settled in the sources, `brainstorm` is skipped entirely and the work
 enters through `specify` directly.
@@ -40,8 +40,7 @@ Triggers:
   long in-context discussion, settled design docs. Use `specify`
   directly: discovery would only re-litigate decisions the sources
   already made.
-- A test-specifiable feature, on a profile that enables `tdd` — use
-  `tdd` directly.
+- A test-specifiable feature — use `tdd` directly.
 - A bug-fix iteration — use `debug` directly.
 - A tidy iteration — use `audit` directly.
 - A trivial mechanical edit — per the project's CLAUDE.md carve-out.
@@ -65,11 +64,11 @@ Before asking any clarifying questions:
 
 - `git log -5 --format=full` for the full bodies of the most
   recent iter / audit commits — current state of the project.
-- If the project has a design ledger configured under
-  `paths.design_ledger`, walk to the relevant contracts for
-  the invariants the new cycle might touch.
-- When reading any file under `paths.design_models` (or the
-  ledger's "model" rows), note its `status` /
+- If the project has a design ledger (its CLAUDE.md project facts name
+  it), walk to the relevant contracts for the invariants the new cycle
+  might touch.
+- When reading any file under the project's design models, if it has
+  them, or the ledger's "model" rows, note its `status` /
   `validated-against` frontmatter if present: `status:
   aspirational` means its code is a target, not verified fact.
   Track which content you may lift from such a source — it is
@@ -196,7 +195,7 @@ The production gates live there, not here.
   when the sources do not resolve a design fork.
 - **Ad-hoc dispatch.** The orchestrator MAY ad-hoc dispatch
   `../planner/agents/plan-recon.md` during Step 1 when the cycle
-  enters code territory not recently read; opt-in, not part of the
+  enters code territory not recently read; ad-hoc, not part of the
   standard process.
 - **Project feature-acceptance criterion:** declared in the project's
   `CLAUDE.md` — applied prospectively by `specify` (its Step 2), not