#10185: fix: pass effective workspace as cwd to Pi SDK createAgentSession

## Summary - In sandbox mode, `createAgentSession()` received `resolvedWorkspace` (the original user workspace) instead of `effectiveWorkspace` (the sandbox directory) - The process had already `chdir`'d into `effectiveWorkspace` (line 166), but the Pi SDK session was initialized with the wrong `cwd`, causing a mismatch - One-line fix: pass `effectiveWorkspace` instead of `resolvedWorkspace` to `createAgentSession` Closes #10136 ## Test plan - [x] Verified `effectiveWorkspace` is correctly computed at lines 158-162 based on sandbox state - [x] Confirmed `process.chdir(effectiveWorkspace)` already uses the correct value (line 166) - [x] The fix aligns `createAgentSession` cwd with the actual process working directory 🤖 Generated with [Claude Code](https://claude.ai/code) <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR fixes a sandbox/workspace mismatch in the Pi embedded runner by passing `effectiveWorkspace` (the sandboxed directory when applicable) as the `cwd` to `createAgentSession()`, aligning the SDK session’s working directory with the process `chdir` and the rest of the runner’s workspace usage. Change is localized to `src/agents/pi-embedded-runner/run/attempt.ts` within `runEmbeddedAttempt()` where the Pi SDK session is created. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is a one-line swap from `resolvedWorkspace` to `effectiveWorkspace` at the Pi SDK session initialization, matching the already-applied `process.chdir(effectiveWorkspace)` and other code paths that consistently use `effectiveWorkspace` for workspace operations. No new logic branches or external side effects were introduced. - No files require special attention <!-- greptile_other_comments_section --> <!-- /greptile_comment -->