[codex] Reduce Docker startup rebuilds

[den-sq]

Summary

• stop forcing a Docker Compose rebuild on production app startup
• route main-server development through python/compose.dev.yml with a bind-mounted Python package and Uvicorn reload
• route plugin-template backend development through backend/compose.dev.yml with a bind-mounted backend/app and FastAPI dev mode
• update Docker build readiness docs and plugin-template docs with the new dev/rebuild split

Refs #78

Validation

• node --check plugins/plugin-template/backend-dev.cjs
• git -C ouroboros diff --check

Not run

• docker compose -f python/compose.dev.yml config could not run because Docker is unavailable in this WSL distro.
• docker compose -f plugins/plugin-template/backend/compose.dev.yml config could not run because Docker is unavailable in this WSL distro.
• npm run typecheck:node could not start because tsc is missing from node_modules/.bin.

[tavateva]

Draft Promotion Review ⚠️ CONDITIONALLY BLOCKED

Reviewed against Draft Promotion Criteria.

Special case: Issue #78 lists 4 components; accepting that each can be a separate PR.

Criterion Assessment

1. CI and mergeability: ⚠️ AMBIGUOUS → FAIL — Mergeable, but 0 CI checks
2. Issue Acceptance Criteria: ⚠️ PARTIAL SCOPE ACCEPTED — This PR addresses 1 of 4 components (hot reloading). Partial implementation is acceptable if issue remains open for remaining components.
3. PR body Test Plan checkboxes: ⚠️ ENVIRONMENTAL BLOCKER — Docker compose validation explicitly gated on Docker availability (unavailable in WSL)
4. Tests run: ⚠️ ENVIRONMENTAL CONSTRAINT — Static checks (node --check, git diff --check) passed; Docker runtime checks blocked by environment
5. Scope: ✅ PASS (revised) — PR scope is hot-reload dev; acceptable as partial implementation of Minimize Docker Builds #78
6. Regressions: ⚠️ LIMITED VERIFICATION — Static checks passed, runtime validation unavailable
7. Judgement calls: ⚠️ NEEDS VERIFICATION

VERDICT: ⚠️ CONDITIONALLY BLOCKED

Remaining Concerns

Primary blocker: Docker compose file changes cannot be runtime-validated in the authoring environment.

Per criterion #3, the deferral is "concretely gated on an external input the author has explicitly surfaced" (Docker unavailable in WSL). However, criterion #4 states tests "must have been executed" — the question is whether environmental unavailability is an acceptable exception.

Remediation Options

Option 1 (recommended): Have another reviewer with Docker access validate the compose files and report results as a comment.

Option 2: If compose file changes are trivial/low-risk (bind mounts, service definitions), accept static validation as sufficient and note that runtime testing is deferred to the first user who runs it.

Option 3: Author obtains Docker access (native Linux, macOS, or different WSL distro with Docker configured) and validates.

Issue #78 Tracking

If this PR is promoted as a partial implementation:

• ✅ Hot Reloading (this PR)
• ⏳ Use GPU containers as base (separate PR needed)
• ⏳ Use container registry (separate PR needed)
• ⏳ Build non-docker .exe files (separate PR needed)

Recommend creating tracking issues for the 3 remaining components or leaving #78 open until all components are addressed.