[LIT-2879] Wave 1: tool surface + run loop + e2e PR test

[ishaan-berri]

Linear

LIT-2879 (Epic C — Agent runtime daemon)

What this PR ships (Wave 1 of 3)

The minimum viable daemon that:

• Boots in session mode
• Registers with the proxy via /v2/sessions/{sid}/internal/register
• Clones a repo (file:// or https with token-injected URL)
• Runs the LLM tool loop (Anthropic SDK, also works against an Anthropic-compatible LiteLLM proxy via ANTHROPIC_BASE_URL + ANTHROPIC_AUTH_TOKEN)
• Executes tool calls locally (read_file / str_replace / shell / grep / glob / todo)
• Streams events back via /v2/sessions/{sid}/runs/{rid}/events:append
• Has a thin gh pr create wrapper ready for end-of-run PR opening (not invoked yet — wired up but the LLM decides when to call it via the shell tool, or Wave 2 adds the autoCreatePr flag)

Validation passing

• pnpm typecheck — clean
• tests/e2e/fix-typo.test.ts — daemon spawns, registers with an in-process mock proxy, clones a tiny throwaway file:// repo, drives the real LLM through the str_replace tool to fix a typo, and emits the expected event sequence (run_started → assistant_message → tool_call → tool_result → run_finished). Verified the file edit actually landed on disk.

Sample local run output (see PR commits for full logs):

```
[daemon] daemon.starting mode=session sessionId=sess_test_e2e
[daemon] session.registered
[daemon] git.clone.done ref=main
[daemon] loop.request iteration=0..4
[daemon] loop.end_turn iterations=4
[daemon] daemon.exited_cleanly
PASS tests/e2e/fix-typo.test.ts (12.6s)
```

Deferred to Wave 2

• .cursor/skills/ + .cursor/hooks.json + .cursor/mcp.json harness loaders
• Warm mode (LITELLM_AGENT_MODE=warm) — entrypoint already routes by mode; warm body throws "reserved for Wave 2"
• Multi-run within a session (workspace persistence is implicit; explicit poll/loop semantics for long-lived sessions)
• Production hydrate path (currently reads LITELLM_HYDRATE_JSON env so the e2e harness can inject; production register-response inline TBD)
• autoCreatePr flag wired into the run loop (helper already exists)

Deferred to Wave 3

• Validations #5 (skills) #6 (hooks) #7 (MCP) #8 (per-team secrets) #9 (network allowlist iptables) #11 (warm mode integration)
• Real EC2 boot via Packer AMI (gated on Epic B merge)
• Daemon restart resilience (validation #10)