refactor(tooling): T-1290 — the assets domain, where OFF is the normal case

tooling/db/ (a misnamed directory: connectors, not database work),
trellis-batch.sh and synth_ui_sounds.py become `reach assets`:
audio {health,generate,batch,post {convert,normalize,trim,pipeline}},
image {health,generate}, trellis {health,generate,batch}, and synth-ui.
The four audio bash wrappers are retired, and tooling/db/ is gone.

Parity, from baselines taken before anything moved:

- the four UI-sound WAVs and the harmonic-synth WAVs (exponential and linear
  decay) are byte-identical
- the ffmpeg pipeline's decoded PCM is identical. Its .ogg bytes are not,
  even between two runs of the OLD code: Ogg picks a random stream serial,
  so the encoded file was never the right thing to compare
- the network success paths can't be run in a gate (Stable Audio and Trellis
  are kept off, Gemini costs money), so tooling/test_assets.py stands up a
  fake Gradio and pins every payload: the audio submit, Trellis's six-call
  session sequence with its 9-input image_to_3d, and the Gemini body. It
  failed when one Trellis value was mutated (7.5 → 7.0)

Failure classification, in endpoints.py, is the point of the port. The
services are OFF by design (VRAM on tower-of-joy, D-17), and the topology doc
warns against "fixing" one by restarting it. So a refused connection says OFF
and asks for the service to be turned on rather than restarted; a 4xx/5xx says
the request was rejected; 401/403 says credentials; 429 says quota; and an
unreachable Gemini blames the network, not VRAM.

Behaviour changes, each a failure that used to read as success or crash:

- audio batch and trellis batch exited 0 with failures in their summaries;
  they now print the summary and exit 1
- trellis generate on a missing image crashed with a TypeError
  (print(..., indent=2)); it now names the file, and checks it before the
  service so a typo is not reported as an outage
- the ffmpeg pipeline left its intermediates behind when a step failed

Structure: the connectors called each other as subprocesses (batch spawned
the connector, which spawned audio_post) and parsed each other's stdout. They
are now function calls, and ffmpeg is the only exec, through core/process.
ensure_venv() is removed: it os.execv'd into .venv, which D-263's exec rule
forbids, and reach declares the dependencies itself. config.json moved into
the domain deliberately, and the local-services rule follows it.

Output contract: results are still JSON on stdout with the same keys, so skill
readers keep working. Failures are an exit status with a Fix line, never
{"ok": false}. The audio-gen, glb-gen and image-gen skills, Araminta's agent
file and the allow-list are updated to match. glb-gen's "trellis-batch.sh is
hardcoded to one category" caveat is gone: batch takes --input-dir or --names.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.claude/agents/README.md

@@ -113,7 +113,7 @@ Synthesize findings.
 
 ### Araminta (Visual Designer)
 - Joins discussions only when visual consistency decisions are needed
-- Drives image-gen/sprite-gen/glb-gen/audio-gen via Bash — no Skill/MCP tool grant, so she invokes the connector scripts directly, e.g. `python3 tooling/db/image_connector.py generate ...`
+- Drives image-gen/sprite-gen/glb-gen/audio-gen via Bash — no Skill/MCP tool grant, so she invokes the connectors directly, e.g. `reach assets image generate ...`
 - **image-gen calls the paid Gemini API (`GEMINI_API_KEY`) — always ask Team Leader for permission before generating. glb-gen/audio-gen run against self-hosted tower-of-joy infrastructure and sprite-gen renders locally, so they don't carry the same per-call cost, but confirm intent before large batch jobs.**
 
 ### SI (Refinement Manager)

.claude/agents/araminta.md

@@ -48,7 +48,7 @@ PBR assets from these sources go through our `toon_masked` shader and come out m
 
 You have `Bash` but no `Skill`/MCP tool grant, so asset generation runs through the project's connector scripts directly, not a slash-skill invocation:
 
-- **image-gen** (`.claude/skills/image-gen/`) — concept art, icons, UI mockups, reference images via the Gemini API: `python3 tooling/db/image_connector.py generate "prompt" --output .tmp/image-gen/[category]/[name].png --aspect 1:1`. Requires `GEMINI_API_KEY` (set in `.claude/settings.local.json`) — this is the one that costs real money per call.
+- **image-gen** (`.claude/skills/image-gen/`) — concept art, icons, UI mockups, reference images via the Gemini API: `reach assets image generate "prompt" --output .tmp/image-gen/[category]/[name].png --aspect 1:1`. Requires `GEMINI_API_KEY` (set in `.claude/settings.local.json`) — this is the one that costs real money per call.
 - **sprite-gen** (`.claude/skills/sprite-gen/`) — flat 2D artwork (paintings, flags, billboards, signage) rendered as PNG textures/decals, via `scripts/render.sh`.
 - **glb-gen** (`.claude/skills/glb-gen/`) — converts a concept PNG to a game-ready `.glb` via Trellis (self-hosted on tower-of-joy) plus Blender post-processing.
 - **audio-gen** (`.claude/skills/audio-gen/`) — ambient loops, SFX, and UI sounds via the self-hosted Stable Audio Open Gradio app (tower-of-joy).