feat: Add existing folder as repository

[PureWeen]

Summary

Allows users to add an already-cloned local folder as a managed repository in PolyPilot. Once added, the folder gets full feature parity with repos cloned through the app: worktree creation, branch checkout, PR checkout, squad file discovery, and sessions.

How it works

The '+ Repo' button in the sidebar now shows two tabs on desktop:

• 🔗 URL — existing flow (clone by GitHub URL/shorthand)
• 📂 Existing Folder — new flow (pick a local folder that's already cloned)

For the folder flow, the user either types a path or clicks … to open the native folder picker. PolyPilot then:

1. Validates the folder exists
2. Confirms it's a git repository (git rev-parse --git-dir)
3. Reads the origin remote URL
4. Runs the normal bare-clone/fetch pipeline using that URL (same as URL mode)

The result is a RepositoryInfo entry in repos.json and a bare clone in ~/.polypilot/repos/ — identical to any other managed repo.

Changes

• RepoManager.AddRepositoryFromLocalAsync — enhanced with validation (folder exists, is git repo, has origin remote), progress callback, and clear error messages
• CopilotService.AddRepoFromLocalFolderAsync — new public method, local mode only
• SessionSidebar.razor — URL/Folder mode tabs, folder path input + browse button (platform-gated), CloseAddRepoForm helper
• SessionSidebar.razor.css — styles for tabs, folder row, browse button
• Tests — 3 new AddRepositoryFromLocal_* tests covering non-existent folder, non-git folder, and git repo with no origin remote

[PureWeen]

🔍 Multi-Model Consensus Review — PR #405 (Round 1)

PR: feat: Add existing folder as repository
CI Status: ⚠️ No CI checks configured on this branch
Models: claude-opus-4.6 ×2, claude-sonnet-4.6, gemini-3-pro-preview, gpt-5.3-codex

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Findings (consensus ≥ 2 models)

🟡 F1: RunProcess test helper — race condition (RepoManagerTests.cs:69-75)
Process.Start() is called on line 69, but p.Exited is subscribed on line 70 and p.EnableRaisingEvents = true is set on line 75. If git init completes between Start() and EnableRaisingEvents = true, the Exited event never fires and the TaskCompletionSource blocks forever — no timeout, no cancellation token. Fix: set EnableRaisingEvents = true and subscribe Exited before Start(), or use await p.WaitForExitAsync(ct).

🟡 F2: Bare catch swallows OperationCanceledException (RepoManager.cs, AddRepositoryFromLocalAsync)

catch { remoteUrl = ""; }

RunGitAsync throws InvalidOperationException on non-zero exit, but if the user cancels via CancellationToken, OperationCanceledException is also caught. The caller then throws a misleading "No 'origin' remote found" instead of propagating cancellation. Fix: catch (Exception ex) when (ex is not OperationCanceledException).

🟡 F3: Same bare catch pattern in IsGitRepositoryAsync (RepoManager.cs)

catch { return false; }

A cancelled git rev-parse reports "not a git repository" instead of propagating cancellation. Same fix as F2.

🟢 F4: Fragile state reset on form open (SessionSidebar.razor:341)
showAddRepo = true inline handler does not reset addRepoFolderMode or addRepoFolderPath. All current close paths go through CloseAddRepoForm() which resets them, but any future close path that sets showAddRepo = false directly would leak stale folder-mode state. Low risk — all current paths are correct.

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✅ Positive Notes

• AddRepoFromLocalFolderAsync in CopilotService.Bridge.cs correctly guards remote mode, follows GetOrCreateRepoGroup pattern, and state persistence is handled (save + notify)
• AddRepositoryAsync already handles duplicate repos gracefully (returns existing)
• CloseAddRepoForm() properly resets all new state variables
• Test coverage for error paths (non-existent folder, no git, no origin) is good

Test Coverage

• ✅ Three failure-mode tests added (NonExistentFolder, NoGit, NoOrigin)
• ⚠️ No success-path test for AddRepositoryFromLocalAsync (bare clone from local)
• ⚠️ No test for AddRepoFromLocalFolderAsync remote-mode guard (InvalidOperationException)

Verdict: ⚠️ Request Changes

Required: Fix F1 (test hang risk) and F2/F3 (cancellation swallowing)
Nice-to-have: F4 state reset, success-path test