feat: causal diagnosis step on every proposal (v0.3.0)

Closes the gap between categorical signal capture (we saw 3 retries) and
causal proposal drafting (here is why and what to do). Mirrors the NL trace
reflection step Hermes Agent uses before mutating prompts.

Adds # Diagnosis section to every proposal body — four labelled lines:
- Trigger: what the user wanted / context
- Action:  what the assistant did
- Mismatch: how the action diverged
- Outcome: surfacing event with >=1 verbatim transcript quote

Constraints:
- <=5 LOC of prose total
- >=1 backtick-wrapped quote <=80 chars from transcript context window
- Cannot speculate; "Mismatch: unclear" is allowed but takes -1 confidence
- Win clusters use "Mismatch: None" with recovery quote in Outcome

Skill enforces structure at apply time (presence + 4 labelled lines + quote)
for both auto-apply and walk-the-queue paths. No semantic check — humans
judge causal correctness during walk-the-queue.

Adds optional frontmatter field `diagnosis_summary` (<=120 chars from the
Mismatch line) so applied/ and rejected/ are searchable by causal pattern.

New rubric penalty: -1 confidence when Diagnosis flags Mismatch: unclear.
Stops weak-causation proposals from auto-applying (drops below conf>=4).

No hook changes. All 27 tests still pass.

Spec: ~/.claude/docs/superpowers/specs/2026-05-10-adam-causal-diagnosis-design.md

skills/adam-self-improvement/SKILL.md

@@ -105,6 +105,7 @@ adam reflect summary:
 
 Before writing any proposal:
 - Confirm `# Assumptions` section is non-empty.
+- Confirm `# Diagnosis` section exists and contains all four labelled lines (`Trigger:`, `Action:`, `Mismatch:`, `Outcome:`) AND at least one backtick-wrapped quote ≤80 chars in the Outcome line. Refuse if missing or malformed — agent must redraft per the "Diagnosis drafting protocol" in `agents/adam.md`.
 - Confirm `# Success criterion` section is non-empty and runnable.
 - Confirm change is ≤50 LOC for non-`skill_new`, or ≤80 LOC for `skill_new` body. If larger, ask the user once: "this proposal is N LOC — proceed?"
 - For `claude_md_edit`: confirm 3+ distinct cwds in the `# Why` section.