Rewire function_app.py; delete swarm_server.py + chat.py (PR 4/4)

[kody-w]

Summary

Final phase of the one-stem-many-swarms refactor. Tier 2 becomes a thin Azure Functions adapter over /api/chat, matching Tier 1's surface per CONSTITUTION Article XV (tier parity runs deeper than agents).

Deletions

File	Lines	Why safe to delete
rapp_brainstem/swarm_server.py	1736	Its capabilities now ship as the 7 swarm-management agents in PR #3. No remaining callers anywhere in the repo.
rapp_brainstem/chat.py	342	LLM tool-calling loop inlined into function_app.py's run_chat (~100 lines).
rapp_brainstem/brainstem_admin_agent.py	—	Root-level sprawl (Article XVI violation). An agents/experimental/ copy already exists.

Total: −2878 lines, +598 lines.

New function_app.py (917 → 470 lines)

• No SwarmStore, Binder, Assistant, STORE, or multi-tenant routing.
• No /api/swarm/<guid>/*, /api/t2t/*, or /api/workspace/* surface.
• Multi-swarm operations flow through /api/chat via the PR Add 7 swarm-management agents (drop-in, stdlib-only) #3 swarm-management agents (Article XIV).
• Routes: /api/chat, /api/health, /api/llm/status, plus OG aliases (/api/businessinsightbot_function, /api/trigger/copilot-studio).
• Agent discovery from BRAINSTEM_HOME/agents/ — same glob pattern as brainstem.py.
• Same tool-calling loop structure, same |||VOICE|||/|||TWIN||| split, same response envelope keys.

build.sh

Now vendors only: llm.py, twin.py, _basic_agent_shim.py, agents/*.py. No more swarm_server.py → server.py rename.

Stale-reference cleanup

• tests/run-tests.mjs — removed chat.py from file-presence list.
• brainstem.py load_agents — removed special-case always-load for the deleted brainstem_admin_agent.py.

Tests

• NEW: tests/test-function-app-chat.sh — 32 assertions. Exercises run_chat directly (no func start required), verifies envelope parity with Tier 1, VOICE/TWIN split, agent discovery, tool-calling loop behavior under LLM_FAKE=1, BRAINSTEM_HOME swap, and Article XIV compliance.
• tests/run-tests.mjs — 61/61 pass.

Known parity gap (deferred to PR #5)

brainstem.py's /chat still uses Copilot-only (call_copilot at line 712). For full Article XV tier parity, it should use llm.py's provider dispatch like function_app.py does — so Tier 1 users can point at Azure OpenAI / OpenAI / Anthropic from one .env change.

That change touches the sacred one-liner install path (Article V) and deserves its own PR with its own rollback story. Not bundled here.

Test plan

• bash tests/test-function-app-chat.sh → 32/32 pass
• node tests/run-tests.mjs → 61/61 pass
• bash rapp_swarm/build.sh produces clean _vendored/ with only llm.py/twin.py/_basic_agent_shim.py/agents/
• python3 -c "import function_app" clean; no SwarmStore/STORE/Assistant symbols
• python3 -c "import brainstem" still clean after special-case removal
• grep confirms no remaining chat.py/swarm_server references in docs or code (only experimental/ copy + web/mobile/ secondary surface, already deferred)

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