fix(aspect+e2e): make tests truthful + add mutex to ums-mcp + install elixir

Two failing checks on PR #149 (and on every PR/main run since at least
2026-05-20) had four distinct root causes. Each fixed at source:

## Aspect — Thread Safety + ABI Contract + SPDX (27 → 0 failures)

1. **Comment-stripping filters were broken.** Aspect 2 (Idris2 banned
   patterns) used `grep -v '^\s*--'` and `grep -v '^\s*|||'` to skip
   line-comments and `|||` doc-comments — but `grep -rn` output is
   `path:lineno:content`, so the line never starts with `--` or `|||`;
   it starts with the path. The filters silently let every commented
   match through, producing two false-positive failures (Admitted in
   `cartridges/fleet-mcp/.../SafeFleet.idr` doc-comment + trailing
   `Echidnabot — ... (Admitted, sorry)` comment). Fixed by anchoring
   the filters at `:[[:space:]]*--` etc., factored into one
   `strip_comments_and_docstrings` helper that also handles trailing
   `-- … <pat>` comment matches.

2. **`believe_me` check didn't exempt class-J axioms.** `src/abi/Boj/
   SafetyLemmas.idr` declares 5 documented class-J `believe_me`
   primitives (`charEqSound`, `charEqSym`, `unpackLength`,
   `appendLengthSum`, `substrLengthBound`) — see PROOF-NEEDS.md / ADR-
   008. Added a `PROOF_EXEMPT` regex so the test passes on documented
   axioms while still failing on any new `believe_me` elsewhere.

3. **Aspect 1 Mutex check was over-aggressive.** It failed any .zig
   file with `pub export fn` + zero `Mutex` references — including
   purely-functional FFI like `cartridges/burble-admin-mcp/ffi/
   burble_admin_ffi.zig` (3 exports, ZERO file-scope globals — table
   lookups + arithmetic over i32). 9 false-positive failures. The
   right invariant: only fail when there's ALSO file-scope mutable
   global state (`^(pub )?var <ident>`). Refined accordingly. Now
   reports purely-functional FFI with a clear pass message.

4. **Aspect 4 lacked a stub/ffi_only status.** 15 cartridges failed
   "incomplete layers (ABI=false ...)" — but ~10 of them are
   manifest-only stubs (cartridge.json declares the API surface, no
   abi/ or ffi/ yet) and ~5 are intentionally proof-free
   observability/glue (boj-health, claude-ai-mcp, lang-mcp,
   orchestrator-lsp-mcp, toolchain-mcp). Added a `"status"` field to
   `cartridge.json` (`complete` (default) / `stub` / `ffi_only`);
   Aspect 4 honours it and reports `(N complete, M stub, K ffi_only)`
   so the categories stay visible.

5. **ums-mcp had a real bug.** 15 C-ABI exports operating on a global
   `var sessions: [MAX_SESSIONS]SessionSlot` array, no Mutex. The
   filter fixes above narrow Aspect 1 to true positives, and this was
   the one left over. Added `var sessions_mu: std.Thread.Mutex` and
   `sessions_mu.lock(); defer sessions_mu.unlock();` to all 14
   sessions-touching exports. `ums_can_transition` is a pure function
   (enum→enum) and stays lock-free. Mirrors the 007-mcp pattern
   (`g_state_mu` in `cartridges/007-mcp/ffi/oo7_mcp_ffi.zig:79`).
   `cd cartridges/ums-mcp/ffi && zig build` passes.

After all five fixes: 115 passed / 0 failed / 1 warning (was 87/27/1).
The one warning (`federation.zig` `catch unreachable` patterns) was
already pre-existing — out of scope here.

## E2E — Full REST + MCP Bridge (failing since 2026-05-20)

`tests/e2e_full.sh` requires `mix` to start the Elixir backend, but
`.github/workflows/e2e.yml` never installed Elixir/OTP. Added an
`erlef/setup-beam@v1.18.2` step (Elixir 1.18 + OTP 27 — matches the
estate convention used in every other repo's hypatia-scan.yml) plus a
`mix deps.get` step before the test runs.

## Foundational follow-up (NOT in this PR)

Same gap as r-g-t-v#89 and absolute-zero#42: `main` branch protection
has no `required_status_checks` block, which is how three workflows
(E2E, OpenSSF Scorecard Enforcer, Instant Sync) have been failing on
main for days without blocking merges. Hypatia PR #316 ships the
BH001/BH002/BH003 rules that detect this class estate-wide.

## Test plan

- [x] `bash tests/aspect_tests.sh` — 115/0/1 (was 87/27/1)
- [x] `cd cartridges/ums-mcp/ffi && zig build` — clean
- [x] All cartridge.json files still valid JSON
- [x] e2e.yml YAML parses; step ordering correct (setup-beam before
      build-FFI / run-e2e)

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

Author: hyperpolymath

.github/workflows/e2e.yml

@@ -56,9 +56,22 @@ jobs:
         with:
           deno-version: v2.x
 
+      - name: Install Elixir + OTP
+        # tests/e2e_full.sh requires `mix` on PATH to start the Elixir
+        # backend (elixir/ — `mix run --no-halt`). Pinned to match the
+        # estate convention (see hypatia-scan.yml across the org).
+        uses: erlef/setup-beam@fc68ffb90438ef2936bbb3251622353b3dcb2f93  # v1.18.2
+        with:
+          elixir-version: '1.18'
+          otp-version: '27'
+
       - name: Install system dependencies
         run: sudo apt-get update && sudo apt-get install -y curl jq
 
+      - name: Fetch Elixir deps
+        working-directory: elixir
+        run: mix deps.get
+
       - name: Build FFI libraries
         run: |
           cd ffi/zig && zig build

cartridges/boj-health/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "boj-health",
   "version": "0.1.0",
+  "status": "ffi_only",
   "description": "BoJ server self-health cartridge — status, ping, and uptime queries. Self-contained Zig FFI (.so) reference implementation: no external services required.",
   "domain": "infrastructure",
   "tier": "Ayo",

cartridges/chromadb-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "chromadb-mcp",
   "version": "0.1.0",
+  "status": "stub",
   "description": "Chroma vector DB — embedded (local persistent) or client/server; LLM-app-focused; metadata + document storage alongside vectors.",
   "domain": "vector",
   "tier": "Teranga",

cartridges/claude-ai-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath)",
   "name": "claude-ai-mcp",
   "version": "0.1.0",
+  "status": "ffi_only",
   "description": "Anthropic Messages API cartridge -- send messages to Claude models, count tokens, manage multi-turn conversations",
   "domain": "AI",
   "tier": "Ayo",

cartridges/echidna-llm-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>",
   "name": "echidna-llm-mcp",
   "version": "0.1.0",
+  "status": "stub",
   "description": "LLM advisor cartridge for the ECHIDNA formal verification engine. Provides free-form consultation (consult) and structured proof-tactic generation (suggest_tactics) by routing to Anthropic Claude via ANTHROPIC_API_KEY.",
   "domain": "Formal Verification",
   "tier": "Ayo",

cartridges/elevenlabs-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "elevenlabs-mcp",
   "version": "0.1.0",
+  "status": "stub",
   "description": "Text-to-speech via ElevenLabs API — high-quality voices, multilingual, voice cloning (premium tier), streaming output.",
   "domain": "multimodal",
   "tier": "Teranga",

cartridges/ffmpeg-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "ffmpeg-mcp",
   "version": "0.1.0",
+  "status": "stub",
   "description": "Local FFmpeg gateway — probe metadata, transcode formats, extract audio, extract frames, concatenate, trim. Glue between whisper / replicate / browser screenshots. Local-only — requires host ffmpeg binary; not Worker-compatible.",
   "domain": "multimodal",
   "tier": "Teranga",

cartridges/lang-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath)",
   "name": "lang-mcp",
   "version": "0.1.0",
+  "status": "ffi_only",
   "description": "Multi-language session manager for the nextgen-languages family: Eclexia, AffineScript, BetLang, Ephapax, MyLang, WokeLang, Anvomidav, Phronesis, Error-lang, Julia-the-Viper, Me-dialect, Oblibeny. Tracks per-language sessions, delegates type-checking and evaluation to each language's CLI tool, and provides a unified interface across all dialects.",
   "domain": "Languages",
   "tier": "Ayo",

cartridges/orchestrator-lsp-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "orchestrator-lsp-mcp",
   "version": "0.1.0",
+  "status": "ffi_only",
   "status": "ready",
   "description": "Cross-domain LSP orchestrator. Routes LSP requests across all 12 poly-*-lsp servers (cloud, container, iac, k8s, db, queue, secret, git, ssg, proof, observability, browser) via a single GenLSP supervisor. Inspired by poly-orchestrator-lsp (polystack, archived). Wraps the 12 domain servers into one unified textDocument interface with domain-routing based on workspace root and file type.",
   "domain": "LSP",

cartridges/pinecone-mcp/cartridge.json

@@ -4,6 +4,7 @@
   "copyright": "Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>",
   "name": "pinecone-mcp",
   "version": "0.1.0",
+  "status": "stub",
   "description": "Pinecone hosted vector DB — serverless indexes, upsert, similarity search, namespaces, metadata filtering.",
   "domain": "vector",
   "tier": "Teranga",