Merge conflicts outside the opened workspace subdirectory are silently hidden

[GordonBeeming]

Split off from PR review feedback on #49.

Original feedback

collect_conflicted_files can fall back to a repo-relative path for conflicts outside the workspace subdirectory. That breaks the contract expected by git_stage_resolved (which resolves paths relative to workspace_root and rejects ..), so the commit panel's "Mark resolved" action will fail or target the wrong path when a merge conflict exists outside the opened subdirectory workspace.

— @copilot-pull-request-reviewer on this review comment

Background

sync_workspace/complete_merge (src-tauri/src/git_sync.rs) operate on the whole Git repository, not just the workspace subdirectory the app has open. If a pull conflicts on a file outside that subdirectory, the merge is genuinely stuck until it's resolved — but collect_conflicted_files (src-tauri/src/git_commit.rs) only knows how to report paths relative to the workspace, so it drops that entry from GitStatus.conflictedFiles rather than exposing an unusable path. The user sees "0 conflicts" while complete_merge keeps refusing with UnresolvedConflicts, with no clue why — a real, if narrow, dead end (subdirectory workspace opened on a repo where a network sync hits a conflict outside it).

Proposed fix

Surface the state honestly instead of listing a path the UI can't act on:

• Add a distinct signal to GitStatus — e.g. conflictsOutsideWorkspace: usize (count) or a boolean — computed alongside conflictedFiles in collect_conflicted_files/status_for_workspace_blocking.
• In the commit panel merge UI, when that count is non-zero, show a message like "N merge conflict(s) exist outside this workspace — resolve them in a terminal" instead of (or alongside) the actionable per-file list, so "Complete merge" staying disabled makes sense to the user.
• stage_resolved/resolve_workspace_path's workspace-scoping (rejecting ..) is a deliberate path-safety boundary and shouldn't be loosened for this.

Source

• PR: Add a Sync control to the commit panel (fetch / pull / push, with live merge-conflict resolution) #49 — Add a Sync control to the commit panel (fetch / pull / push, with live merge-conflict resolution)
• File: src-tauri/src/git_commit.rs:252 (collect_conflicted_files)