feat(ultraplan-local): M1 — profile recommendation flow in ultrabrief

Adds the profile recommendation step to /ultrabrief-local Phase 4. The
brief stays universal (same questions, same template); the new step is
purely a processing-decision layer that records which profile downstream
commands should apply.

What lands:
- agents/profile-recommender.md — new sonnet agent that scores available
  profiles against the finalized brief (keyword + NFR-signal matching,
  axis bumps, hallucination gate that forbids inventing profile names).
  Emits a fenced JSON block with ranked entries.
- templates/ultrabrief-template.md — frontmatter gains
  recommended_profile, profile_match, profile_rationale (default values
  applied when only `default` is available — true at M1).
- commands/ultrabrief-local.md — Phase 4 gains Step 4h with explicit
  branches: short-circuit when only `default` exists; AskUserQuestion
  confirmation when top score ≥ 0.7; explicit fallback message when below
  threshold; manual selection sub-question on user override. Persists the
  three frontmatter fields to brief.md after user confirmation. JSON
  parser failure falls back to `default` with `profile_match: fallback`
  rather than blocking — silent fallback is the worst outcome, but a
  *visible* fallback is acceptable.
- scripts/profile-loader.mjs — adds selectRecommendation(ranked, opts) +
  RECOMMENDATION_THRESHOLD=0.7 export. Single source of truth for the
  threshold logic so the command spec and the helper agree.
- scripts/profile-loader.test.mjs — 10 new tests for selectRecommendation
  (default-only, empty/malformed input, above/below threshold, custom
  threshold, max-by-score, missing fields). Total now 36/36.
- README.md / CLAUDE.md / marketplace landing — docs reflect M0 + M1
  shipped, M2 + M3 still pending.

In practice nothing changes for users at M1 because only `default` is
available — Step 4h takes the short-circuit path and writes
`profile_match: default-only`. M2 ships the additional profiles that
make the recommender meaningful.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/ultraplan-local/templates/ultrabrief-template.md

@@ -10,6 +10,9 @@ research_status: pending         # pending | in_progress | complete | skipped
 auto_research: false             # true if user opted into Claude-managed research
 interview_turns: {N}
 source: {interview | manual}
+recommended_profile: default     # ultraplan-local profile name (M1+)
+profile_match: default-only      # exact | partial | fallback | user-override | default-only
+profile_rationale: "Single profile available; no recommendation made."
 ---
 
 # Task: {title}