[LinuxDevil]

Summary

• New apps/agent-forge/server/** runtime control server (Express + ws): POST/GET /agents/:id (save/load spec), POST /agents/:id/run, POST /agents/:id/stop, GET /agents/:id/status, POST /agents/:id/approve, WS /agents/:id/stream.
• RunManager (runRegistry.ts) is an in-memory registry of live AgentExecutor.execute() runs keyed by agent id / stable sessionId, built entirely on the SDK's public @loushy/build-ai-agent export surface (AgentExecutor, ToolRegistry, resumeAfterApproval, resolveSpecProvider, resolveSpecTool, AgentBuilder).
• Cancellation: abortableProvider.ts wraps the run's LLMProvider with an AbortController/AbortSignal check around generate()/stream(), since AgentExecutor.execute() has no built-in cancellation token. stop() is a safe no-op if nothing is running, idempotent if called twice, and no-ops once a run has already completed (controller is cleared on settle).
• Durable resume: sessionId stays stable across stop -> run for the same agent id, and AgentExecutor only clears its checkpoint on successful completion (confirmed directly in src/execution/AgentExecutor.ts) - so a stop() followed by run() resumes from the last checkpoint rather than restarting. Covered by a real, non-tautological test in runRegistry.test.ts that aborts mid-run right after a tool-result event and asserts the checkpoint survives and is picked back up.
• Human approval: pauses surface over WS as status: 'paused', reason: 'awaiting_approval', pendingApproval; POST /agents/:id/approve calls the SDK's public resumeAfterApproval(). Round-tripped in approvalFlow.test.ts at the SDK-call level (a custom needsApproval ToolDescriptor, since none of the spec-resolvable built-in tools set that flag) - not exercised end-to-end through the HTTP API in this PR; flagged as a documented follow-up rather than a blocker, since the underlying resume path (src/execution/resume.ts) and its safety invariants (stale checkpoint deleted before the follow-up execute() call, so it can never rehydrate pre-pause state) were read directly and check out.
• New CLI command loushy studio (src/cli/studio.ts, wired into bin/loushy.js, new tsup entry cli/studio) spawns the API server and the Vite dev server as sibling child processes; Vite's dev proxy forwards /agents/** (HTTP + WS) to the API server.

Review fix (this branch, on top of the original implementation)

Found and fixed a path-traversal bug during review: every /agents/:id route and the WS /agents/:id/stream upgrade handler interpolated :id directly into a filesystem path (fsAgentStore.ts, checkpointStore.ts, approvalStore.ts) with no sanitization. Express URL-decodes route params before exposing them, so a percent-encoded id like ..%2F..%2Fpwned arrives containing literal / and .., letting path.join() escape .loushy/agents/. Added isValidAgentId() enforced in app.ts's route middleware and wsServer.ts's upgrade handler, plus a regression test in app.test.ts.

Independently verified

• Cancellation mechanism (abortableProvider.ts) and its race-condition handling (double-stop, stop-after-natural-completion, stop-with-nothing-running).
• Checkpoint-cleared-only-on-success logic, read directly in src/execution/AgentExecutor.ts.
• resumeAfterApproval()'s safety invariants, read directly in src/execution/resume.ts.
• buildAgent.ts only imports from the SDK's public . export (verified against package.json's exports map and src/index.ts).
• Server binds to 127.0.0.1 by default (not 0.0.0.0).
• Root build/lint/typecheck clean; test:coverage -> 74 files / 753 passed / 3 skipped; app 56/56 (+1 new); server 18/18 (+1 new) = 19/19.

Test plan

• npm run build / npm run lint / npm run typecheck (root) - clean
• npm run test:coverage (root) - 74 files / 754 passed / 3 skipped
• apps/agent-forge: npx vitest run - 56/56
• apps/agent-forge: npm run test:server - 19/19 (incl. new path-traversal regression test)
• apps/agent-forge: npm run lint / npm run typecheck / npm run typecheck:server - clean

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