fix(windows): hide console window for git child processes

[yushengruohui]

Fixes #485.

Summary

On Windows, the daemon flashes a black git.exe console window on every auto-sync. The cause is execFileSync('git', …) call sites in the daemon's code paths missing windowsHide: true. This PR adds the option to all 7 sites; the change is a one-liner per call site and a no-op on macOS/Linux.

Root cause

The daemon is launched with detached: true (mcp/index.ts, the existing spawn(process.execPath, …) call), which deliberately leaves it without a parent console. On Windows, when a Console-subsystem child (git.exe) is started from a console-less parent, Windows allocates a fresh console window for it unless CREATE_NO_WINDOW is set. Node maps windowsHide: true to CREATE_NO_WINDOW. Without it, every short-lived git invocation flashes its own window. The daemon launcher itself already passes windowsHide: true — it's the git call sites that were missed.

Call sites changed (7 total)

File	Function / line	git command
src/extraction/index.ts	collectGitFiles shared gitOpts	ls-files -c --recurse-submodules, ls-files -o --exclude-standard
src/extraction/index.ts	getGitVisibleFiles	rev-parse --show-toplevel
src/extraction/index.ts	getGitVisibleFiles	check-ignore -q
src/extraction/index.ts	getGitChangedFiles	status --porcelain --no-renames
src/sync/worktree.ts	gitWorktreeRoot	rev-parse --show-toplevel
src/sync/git-hooks.ts	isGitRepo	rev-parse --is-inside-work-tree
src/sync/git-hooks.ts	gitHooksDir	rev-parse --git-path hooks

The fix is the same one-line addition (windowsHide: true) on each options object.

Verification

1. Apply the patch and rebuild (npm run build).
2. Restart the daemon: kill the PID in .codegraph/daemon.pid, then trigger any CodeGraph CLI/MCP call so it respawns.
3. Edit files in an indexed repo at >1 write/sec. The git.exe console window should no longer flash. .codegraph/daemon.log still shows the [CodeGraph MCP] Auto-synced N file(s) in <ms>ms lines — i.e. the sync still runs, just hidden.
4. macOS/Linux: windowsHide is ignored, behavior unchanged.

Notes for reviewers

• extraction/wasm-runtime-flags.ts uses spawnSync(process.execPath, …, { stdio: 'inherit' }) — the relaunch shim spawns Node from a Node parent that already owns a console, so no new window is allocated and no change is needed.
• Optional follow-up (not in this PR to keep the diff minimal): extract a runGit(args, opts) helper that injects windowsHide: true so this can't regress.