feat(core): wire review rules + settings into live reviewSummary (T-CR-501/502)

[matze4u]

What

Wires the shipped-but-dead road-to-code-review Phase-5 seams into the live IDE
review path. GitHandler.reviewSummary (the entry point an IDE "Review changes"
action calls) ran the review engine with hard-coded defaults and never read the
workspace review config — loadReviewRules and the ReviewSettings helpers
(resolveReviewSettings / voteOptionsFromSettings / applySeverityFloor) were
fully tested with zero live callers.

Changes

• T-CR-501 (rules). reviewSummary loads .event4u-agent/review-rules.md
  best-effort and passes it as pipeline.rules, so a project's review rules
  reach the Stage-1 system prompt.
• T-CR-502 (settings). New review/settings-source.ts::loadReviewSettings
  reads .agent-settings.yml :: review (fail-open to schema defaults; does
  not extend AgentSettingsSchema → no config → review coupling). Its
  values drive runReview's vote options and the severity floor, applied to
  issues + potentialIssues before summarizeReview so the counts, top
  findings, and potential tally stay consistent.
• Both readers are optional injected GitHandlerDeps (default to the real file
  readers) — the handler stays pure and unit-testable.

Safety

The severity floor never hides a security finding (security_always_error
exemption) — the trap both council members flagged. A regression test asserts a
low-severity security finding survives a high floor while a low-severity bug
is dropped. Unconfigured workspaces are unchanged (no rules block; default
settings = groupSize 5, floor info).

AI Council (gemini-cli 0.41.2 + codex-cli 0.134.0, 2026-06-02)

• Q0=A (unanimous) — wire rules + settings together.
• Q2=A (unanimous) — apply the floor before summarising.
• Q3=A (unanimous) — unconditional best-effort load (readers fail-open).
• Q4=A (unanimous) — inject optional loadReviewRules?/loadReviewSettings?
  readers into GitHandlerDeps.
• Q1 (settings source) — divergence, synthesised. gemini chose inject-into-deps,
  codex chose review-owned-no-coupling. Resolution: the default reader lives in
  review/settings-source.ts (review-owned, no schema coupling) and is
  injected as a dep (handler stays pure). See ADR-051.

Verification

• task ci exit 0 — lint, format (incl. markdown), build, typecheck, test
  (core 1141 pass / 1 skip; +11 new tests).
• Pure-core TypeScript: no protocol / DTO / codegen change → JetBrains + package
  matrix jobs unaffected.
• No checkbox flip — T-CR-501/502 were already [x]; this lands the live
  wiring their cores were built for. Done-comments updated to cite it.

ADR-051.