fix(incremental): drop invalid --no-renames=false from git diff

The flag --no-renames=false isn't valid git syntax (it's parsed as a
file path). Git's default rename detection is on; removing the flag
keeps that behavior.

Caught while running an end-to-end smoke test against a small fixture
repo: incremental setup failed with 'Command failed: git diff
--name-status -z --no-renames=false ...'. After the fix, the
incremental path runs cleanly: closure is computed, hydrate phase
loads unchanged-file state from DB, parse phase only re-parses files
in closure, and the writeback updates only changed nodes/edges.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

gitnexus/src/core/incremental/git-diff.ts

@@ -60,7 +60,6 @@ export function getChangedFilesSinceCommit(
     'diff',
     '--name-status',
     '-z',
-    '--no-renames=false',
     `${lastCommit}`,
     'HEAD',
   ]);