feat(ios): author 5 iOS device-farm skill templates + generated docs

Authors ios-qa, ios-fix, ios-design-review, ios-clean, ios-sync as upstream gstack skills. Each follows the standard SKILL.md.tmpl pattern with preamble-tier:3 frontmatter. The fork at time-attack/gstack shipped these but as byte-identical .md/.tmpl pairs that wouldn't pass skill-docs.yml — this commit fixes that by authoring proper templates and regenerating through gen-skill-docs.

ios-sync/SKILL.md.tmpl

@@ -0,0 +1,95 @@
+---
+name: ios-sync
+preamble-tier: 3
+version: 1.0.0
+description: |
+  Regenerate the iOS debug bridge against the latest upstream gstack
+  templates. Updates StateServer.swift, DebugOverlay.swift, Package.swift,
+  and the typed @Observable state accessors. Use after you upgrade gstack
+  or add new ViewModels/properties that need accessor coverage.
+  Use when asked to "resync the iOS debug bridge", "regenerate iOS
+  accessors", or "update the gstack iOS instrumentation". (gstack)
+voice-triggers:
+  - "resync the iOS debug bridge"
+  - "regenerate iOS accessors"
+  - "update the gstack iOS instrumentation"
+allowed-tools:
+  - Bash
+  - Read
+  - Write
+  - Edit
+  - Glob
+  - Grep
+  - AskUserQuestion
+triggers:
+  - resync the ios debug bridge
+  - regenerate ios accessors
+  - update the gstack ios instrumentation
+---
+
+{{PREAMBLE}}
+
+# Resync the iOS debug bridge
+
+After `/ios-qa` is installed in an app, the user may:
+
+1. Add new `@Observable` classes or properties that need accessor coverage.
+2. Upgrade gstack to a newer version with hardening fixes.
+3. Move the `@Snapshotable` marker to a different field.
+
+This skill regenerates the relevant artifacts in place.
+
+**Templates live in upstream gstack.** This skill resolves them from
+`~/.claude/skills/gstack/ios-qa/templates/` (or the worktree's
+`ios-qa/templates/` when developing gstack itself). The fork's HTTP-fetch
+pattern is gone.
+
+## Phase 1: Detect installed version
+
+1. Read `<app>/DebugBridgeGenerated/.gstack-version` (written by /ios-qa
+   during install). If missing, treat the install as "unknown old version".
+2. Read upstream version from `$GSTACK_HOME/ios-qa/.gstack-version` (or the
+   value baked into the installed gstack binary).
+3. If versions match AND no new `@Observable` classes were added, exit
+   early with "already up to date".
+
+## Phase 2: Regenerate codegen output
+
+Run `gstack-ios-qa-regen` (or the underlying SwiftPM tool directly):
+
+```bash
+swift run --package-path "$GSTACK_HOME/ios-qa/scripts/gen-accessors-tool" \
+  gen-accessors --input "$APP_SOURCE_DIR" --output "$APP_SOURCE_DIR/DebugBridgeGenerated"
+```
+
+The composite-hash cache key handles whether anything actually needs
+regenerating; if Swift version, generator git rev, lockfile, source content,
+and platform triple all match the cache, this is a ~50ms no-op.
+
+## Phase 3: Update templated Swift files in place
+
+For each file that comes from `ios-qa/templates/*.swift.template`:
+
+1. Read the current installed file at
+   `<app>/DebugBridgeGenerated/<Name>.swift`.
+2. Read the upstream template at
+   `$GSTACK_HOME/ios-qa/templates/<Name>.swift.template`.
+3. If the installed file has a `// GSTACK-EDIT-LINE` marker, fold the user's
+   edits forward.
+4. Otherwise, replace the file outright with the new template (after
+   AskUserQuestion if the diff is non-trivial).
+
+## Phase 4: Verify
+
+1. `swift build` succeeds against the app's package.
+2. `xcodebuild -scheme <SchemeName>` succeeds.
+3. Re-launch the app on the device; daemon connects + rotates token.
+4. `GET /state/snapshot` returns the new accessor schema hash.
+
+## Failure modes
+
+| Symptom | Action |
+|---|---|
+| Swift compile fails after regen | Revert via `git restore` + AskUserQuestion: surface the compile error |
+| Schema hash unchanged after adding new @Observable | The new class isn't marked `@Snapshotable` — the codegen excludes it correctly. If the user wanted it snapshotted, add the wrapper. |
+| `--input` source dir contains test fixtures | gen-accessors scans the input dir recursively; exclude test/ via `--exclude` |