Pipeline Integrate.hs: deterministic cherry-pick

Create Omni/Pipeline/Integrate.hs - deterministic cherry-pick integration.

Depends on: Omni/Pipeline/Core.hs, Omni/Pipeline/Git.hs, Omni/Pipeline/Verify.hs, Omni/Pipeline/Workspace.hs

Replaces the LLM integrator. Pure shell operations, no agent.

Function:

• integrateTask :: WorkspacePool -> FilePath -> Text -> Text -> Maybe Text -> IO IntegrateResult

-- (pool, repoRoot, taskId, baseBranch, maybeNamespace) -- 1. Ensure integration worktree is on baseBranch -- 2. Cherry-pick task commit -- 3. Run verifyOnBase -- 4. If pass: return Integrated commitHash -- 5. If cherry-pick conflict: abort, return Conflict details -- 6. If verify fail: revert cherry-pick, return VerifyFailed details

On success, caller is responsible for:

• Marking task Done
• Cleaning up task branch and dev worktree (via releaseWorkspace)
• Adding summary comment

Verify: typecheck.sh Omni/Pipeline/Integrate.hs