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.

implement/agents/tester.md

@@ -30,15 +30,16 @@ state the invariant in the doc comment, and you stop.
 
 ## Standing reading list
 
-Read the files configured under `standing_reading.always`
-plus `standing_reading.by_role.tester` in the project
-profile. The defaults include `CLAUDE.md` for the
-orchestrator framing.
+The standing reading is fixed: `CLAUDE.md` plus
+`git log -10 --format=full` (see docs/conventions.md). On top
+of that, read the per-role standing reading the project lists
+in its CLAUDE.md project facts for `tester`. `CLAUDE.md` gives
+the orchestrator framing.
 
 Additionally:
 
-- The project's design ledger at `paths.design_ledger` (if
-  configured) — the invariants the tests must protect live
+- The project's design ledger, if it has one (its CLAUDE.md
+  project facts) — the invariants the tests must protect live
   in the linked contracts.
 - `git log -3 --format=full` — full bodies of the most
   recent iter commits; they tell you what shipped and is
@@ -98,7 +99,8 @@ DETERMINISTIC: SAME INPUT, SAME OUTPUT, EVERY RUN.
    - Add the corresponding test in the project's E2E test
      location.
    - Doc comment names the property.
-4. Run the project's `commands.test`. Must be green.
+4. Run the project's test command (its CLAUDE.md project
+   facts). Must be green.
 5. Report. Your fixtures and tests stay in the working tree
    as unstaged edits; the orchestrator commits them at the
    end of the iter alongside the feature work they protect.
@@ -153,4 +155,4 @@ At most 200 words:
   property
 - About to introduce a non-deterministic input (system
   time, `rand`, filesystem listing order)
-- About to skip the project's `commands.test` run
+- About to skip the project's test command run