feat(catalog): T4 — catalog trim + proactive-suggestions.json (Phase A.4)

Shortens frontmatter `description:` in every Claude SKILL.md to a single
lead sentence + (gstack) tag. The routing prose ("Use when asked to...",
"Proactively suggest...") and voice triggers move to a "## When to invoke"
body section so they remain discoverable inside the skill. A per-run
registry at scripts/proactive-suggestions.json aggregates the routing/
voice text for all 52 skills so agents can pull guidance on demand
without paying for it in the always-loaded catalog.

Build flag --catalog-mode=full restores v1.44 legacy behavior (full
multi-line descriptions in frontmatter). Default is trim.

splitCatalogDescription() extracts: lead sentence, routing paragraphs,
voice-triggers line, (gstack) tag presence. Short descriptions (<120
chars, already trimmed) are skipped via a guard so re-runs are idempotent.

Measured impact (vs v1.44.1 baseline):
- Catalog tokens (sum of description bytes / 4): 9,319 → 4,045  (-56.6%)
- Total SKILL.md corpus bytes:                   2,915 KB → 2,880 KB (-1.2%)
- Routing prose preserved as in-skill "## When to invoke" sections
- 52 skill entries in scripts/proactive-suggestions.json (on-demand registry)

The corpus drop is small because catalog trim MOVES text from frontmatter
to body, it doesn't delete it. The headline win is the catalog: the
always-loaded system prompt surface drops by more than half.

Test plan:
- bun test test/gen-skill-docs.test.ts: 389 pass, 0 fail
- Manual: ship/SKILL.md frontmatter description is now ONE line ending
  with `(gstack)`; allowed-tools field on next line (YAML well-formed)
- Manual: scripts/proactive-suggestions.json contains 52 entries
- bun run gen:skill-docs --catalog-mode=full restores legacy behavior

53 files changed (52 SKILL.md across hosts + the new proactive-suggestions.json).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plan-tune/SKILL.md

@@ -2,19 +2,7 @@
 name: plan-tune
 preamble-tier: 2
 version: 1.0.0
-description: |
-  Self-tuning question sensitivity + developer psychographic for gstack (v1: observational).
-  Review which AskUserQuestion prompts fire across gstack skills, set per-question preferences
-  (never-ask / always-ask / ask-only-for-one-way), inspect the dual-track
-  profile (what you declared vs what your behavior suggests), and enable/disable
-  question tuning. Conversational interface — no CLI syntax required.
-
-  Use when asked to "tune questions", "stop asking me that", "too many questions",
-  "show my profile", "what questions have I been asked", "show my vibe",
-  "developer profile", or "turn off question tuning". (gstack)
-
-  Proactively suggest when the user says the same gstack question has come up before,
-  or when they explicitly override a recommendation for the Nth time.
+description: Self-tuning question sensitivity + developer psychographic for gstack (v1: observational). (gstack)
 triggers:
   - tune questions
   - stop asking me that
@@ -35,6 +23,21 @@ allowed-tools:
 <!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
 <!-- Regenerate: bun run gen:skill-docs -->
 
+
+## When to invoke this skill
+
+Review which AskUserQuestion prompts fire across gstack skills, set per-question preferences
+(never-ask / always-ask / ask-only-for-one-way), inspect the dual-track
+profile (what you declared vs what your behavior suggests), and enable/disable
+question tuning. Conversational interface — no CLI syntax required.
+
+Use when asked to "tune questions", "stop asking me that", "too many questions",
+"show my profile", "what questions have I been asked", "show my vibe",
+"developer profile", or "turn off question tuning". 
+
+Proactively suggest when the user says the same gstack question has come up before,
+or when they explicitly override a recommendation for the Nth time.
+
 ## Preamble (run first)
 
 ```bash