slice 3.5c: seed 15 built-in skills across the 6 stacks

Hand-authored skill catalog anchored to real 2026-07 versions:
  - Rust 1.97.1 (stable), edition 2024
  - React 19.2.7, Server Components + Actions
  - TailwindCSS 4.3.3 (CSS-first config, Oxide engine)
  - three.js r185 (WebGPURenderer stable, BatchedMesh matured)
  - React Native 0.86 / Expo SDK 54+ (New Architecture default)
  - cargo-nextest 0.9.140, gitleaks 8.20+, cargo-audit 0.21+
  - Postgres 17 (18 in beta, don't rely on)
  - CUDA Blackwell, Metal Apple7+, ROCm CDNA3

Ships 15 skills across the categories:
  foundation/  workspace-repo-commit-protocol
               small-focused-commits
               tdd-red-green-refactor
               code-review-checklist
               int-xx-marker-protocol
               decompose-int-items
  rust/        write-rust-current-edition
               rust-error-handling
               cargo-test-driven-development
               rust-async-tokio-idioms
  backend/     postgres-migrations-forward-only
               postgres-index-selection
               api-pagination-day-1
  frontend/    react-19-server-components
               tailwind-v4-idioms
               component-4-state-model
  mobile/      expo-managed-vs-bare
               rn-flashlist-perf
  gpu/         gpu-coalescing-and-occupancy
               roofline-model
  threejs/     threejs-perf-and-teardown
  security/    cargo-audit-workflow
               secret-scanning-gitleaks

skills_loader.rs walks skills/**/*.md, parses YAML frontmatter
(name, description, when_to_use, tags), upserts via
skills_catalog::upsert_builtin. Idempotent per boot — bumps version
+ appends skill_versions row ONLY when body changes. Deterministic
sha256-derived ids so builtins are stable across boots.

Dockerfile copies skills/ to /etc/clawmates/skills. Server boot
task spawns loader alongside team_template_loader.

Follow-ups (Slice 3.5c continuation, future PRs):
  - 20-30 more skills (duckdb, shadcn composition, a11y, WebGPU
    migration, metal frame capture, rocprof, deep gitea forge
    integration, semgrep rulepacks)
  - Bind skills to team template roles (add [role.skills] refs to
    templates/teams/*.toml + wire template_role_skills population
    in team_template_loader)

Co-Authored-By: Claude Opus 4.7 <[email protected]>

skills/foundation/int-xx-marker-protocol.md

@@ -0,0 +1,44 @@
+---
+name: int-xx-marker-protocol
+description: The literal line-based markers the mission loop parses to advance state — TASK, WORK, HANDOFF, TEST_PASS, REVIEW_APPROVE, COMPLETED.
+when_to_use: Pin on every coding role. Missing or malformed markers cause the mission to stall.
+tags: [foundation, protocol]
+---
+
+# INT-XX marker protocol
+
+Missions parse your turn output line-by-line for these markers. **They must appear literally**, with the colon, on their own line, no bold, no code fence.
+
+## The full ladder
+
+```
+TASK: INT-NN — <title>              # planner opens a new item
+PLAN_COMPLETE: INT-NN                # planner is done specifying
+WORK: INT-NN                         # coder starts implementing
+HANDOFF: INT-NN                      # coder passes to tester/reviewer
+TEST_PASS: INT-NN                    # tester confirms green
+TEST_FAIL: INT-NN — <reason>         # tester failed the build; coder loops
+REVIEW_APPROVE: INT-NN               # reviewer OKs the diff
+REVIEW_BLOCK: INT-NN — <reason>      # reviewer requests changes
+COMPLETED: INT-NN                    # committer pushed; loop advances
+```
+
+## Rules
+
+1. **Exactly one INT id per marker line.** `COMPLETED: INT-05, INT-06` won't parse.
+2. **Emit at the end of your substantive turn**, not the beginning. Otherwise the parser advances state before the work is real.
+3. **Never emit a marker you can't back up.** Emitting `COMPLETED: INT-NN` without a corresponding `git push` desynchronizes the mission from the repo.
+4. **`REORDER: <one-sentence rationale>`** if you're taking an INT out of order — the loop's review timeline logs these.
+
+## What the loop does with each
+
+- `TASK` + `WORK` + `HANDOFF` are observability only — they show up in the mission's task-card feed (Slice 5).
+- `TEST_FAIL` / `REVIEW_BLOCK` re-schedules the item back to the coder.
+- `COMPLETED` bumps `mission_tasks.status = 'complete'` and advances the loop's `consumed_int_ids`. Next iteration picks the next unconsumed INT.
+- `REORDER` writes a `loop_reorder_event` row — a reviewer can inspect why the order shifted.
+
+## Common failures
+
+- **Marker in a code fence**: `\`\`\`COMPLETED: INT-05\`\`\`` won't parse. Put it OUTSIDE the fence.
+- **Marker with markdown emphasis**: `**COMPLETED: INT-05**` won't parse.
+- **Wrong dash**: `INT-NN — title` uses en-dash; `INT-NN - title` also works. `INT-NN – title` (em-dash) also works. Any dash-like char is fine; the parser trims whitespace around it.