feat(ios): demote the four ios skills to preamble-tier 2 (Phase 5)

They never consume the tier-3 sections (repo-mode ownership, search-before-
building) but do fire AskUserQuestion, which tier >=2 provides — verified by
grep before the plan review. -2.2KB per skill. Render assertions pin the
demotion (tier-3 sections absent, AUQ format present).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ios-sync/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: ios-sync
-preamble-tier: 3
+preamble-tier: 2
 version: 1.0.0
 description: Regenerate the iOS debug bridge against the latest upstream gstack templates. (gstack)
 allowed-tools:
@@ -341,24 +341,6 @@ Write (only after confirmation for free-form):
 
 Exit code 2 = rejected as not user-originated; do not retry. On success: "Set `<id>` → `<preference>`. Active immediately."
 
-## Repo Ownership — See Something, Say Something
-
-`REPO_MODE` controls how to handle issues outside your branch:
-- **`solo`** — You own everything. Investigate and offer to fix proactively.
-- **`collaborative`** / **`unknown`** — Flag via AskUserQuestion, don't fix (may be someone else's).
-
-Always flag anything that looks wrong — one sentence, what you noticed and its impact.
-
-## Search Before Building
-
-Before building anything unfamiliar, **search first.** See `~/.claude/skills/gstack/ETHOS.md`.
-- **Layer 1** (tried and true) — don't reinvent. **Layer 2** (new and popular) — scrutinize. **Layer 3** (first principles) — prize above all.
-
-**Eureka:** When first-principles reasoning contradicts conventional wisdom, name it and log:
-```bash
-jq -n --arg ts "$(date -u +%Y-%m-%dT%H:%M:%SZ)" --arg skill "SKILL_NAME" --arg branch "$(git branch --show-current 2>/dev/null)" --arg insight "ONE_LINE_SUMMARY" '{ts:$ts,skill:$skill,branch:$branch,insight:$insight}' >> ~/.gstack/analytics/eureka.jsonl 2>/dev/null || true
-```
-
 ## Completion Status Protocol
 
 When completing a skill workflow, report status using one of:

ios-sync/SKILL.md.tmpl

@@ -1,6 +1,6 @@
 ---
 name: ios-sync
-preamble-tier: 3
+preamble-tier: 2
 version: 1.0.0
 description: |
   Regenerate the iOS debug bridge against the latest upstream gstack