🤖 Apply lean Athanor review fixes

Adept dispatches no longer pass a model alias over the pin. Igor checks
the stamped model id of plan, attack and phase-review outputs before
acting on them. Implementation work no longer goes to the Athanor as an
unplanned brief. The spawning reference says plainly that "verified"
means read from the schema, marks fork availability unverified, and
cites the 184/184 evidence for alias-over-pin. Minor consistency fixes:
trunk notes, re-check failure path, staging, fallout diffs, run-log
timing.

plugins/spire/skills/implementation/SKILL.md

@@ -44,14 +44,14 @@ Plan-writing tools are swappable (superpowers `writing-plans` today; others late
 
 Both extremes have failed. Many tiny fresh implementers relearn the code each time and fragment the plan. One implementer kept across many tasks bloats and drifts. Choose per block: how much shared understanding does it need, and how much room is left? Context figures in `references/models.md` are guesstimates, not limits.
 
-One option is **trunk and forks**. At intake the builder reads the build plan and the code it touches (the trunk) and writes short trunk notes. Complex blocks in the trunk's area go to a fork of the builder, which inherits its context and model. Mechanical or distant blocks go to a fresh agent that reads the trunk notes. Which harness behaviour is verified and which is assumed: `references/spawning-claude-code.md`.
+One option is **trunk and forks**. At intake the builder reads the build plan and the code it touches (the trunk) and writes short trunk notes. Complex blocks in the trunk's area go to a fork of the builder, which inherits its model and (assumed) its context. Mechanical or distant blocks go to a fresh agent that reads the trunk notes. Which harness behaviour is verified and which is assumed: `references/spawning-claude-code.md`.
 
 ## Phase review, fix, stop
 
 - A **fresh** reviewer that did not build the phase, dispatched outside the build, stamps its model id in its report header. A review without a stamped id does not count.
 - It is adversarial: it runs the gates, traces concrete scenarios, and **answers every deviation and flag in the handoff notes**, one by one. It looks specifically for **weakened checks** (loosened assertions, downgraded errors) and **tests that cannot fail**.
 - **One fix pass** over all findings. Minors are fixed in that pass or logged as follow-ups.
-- **Re-check only Critical and Important**, by a fresh reviewer scoped to those findings. Then stop.
+- **Re-check only Critical and Important**, by a fresh reviewer scoped to those findings. Then stop. A Critical or Important that survives the re-check goes to the user or into a new plan, not into the next phase.
 - Extra reviews (for example a mid-phase review of a hotspot block whose note flags a deviation) are a choice with a stated reason, not a default.
 
 ## Bugs