fix(ci): restore memory CODEOWNERS coverage

[GautamSharma99]

Summary

Fixes #3585.

The memory filesystem and git implementation entries in .github/CODEOWNERS still referenced pre-rename camelCase filenames. GitHub silently ignored those unmatched paths, so changes to durable memory storage could bypass the intended @letta-ai/system-prompt-owners review request.

This PR restores the ownership rules and adds a repository check that catches stale literal CODEOWNERS paths after future moves or renames.

Ownership changes

Replaced the stale entries with the current implementation paths:

• /src/agent/memory-filesystem.ts
• /src/agent/memory-git.ts

Also added the deliberately scoped rule:

• /src/agent/memory-git-*.ts

That rule covers the extracted git implementation modules currently owned with the core implementation:

• memory-git-config-lock.ts
• memory-git-hooks.ts
• memory-git-signing.ts

It does not sweep in dot-named tests such as memory-git.auth.test.ts or memory-git.retry.test.ts.

Regression prevention

Added scripts/check-codeowners-paths.js and wired it into bun run check as the new CODEOWNERS paths gate.

The validator:

• parses non-comment CODEOWNERS entries with source line numbers;
• verifies literal root-relative files and directory rules against the repository tree;
• supports unanchored literal names by looking for an exact filename anywhere in the tree;
• skips supported * and ? glob rules instead of incorrectly requiring them to name one literal path;
• compares exact directory-entry spelling instead of relying on existsSync(), so case mistakes fail even on case-insensitive macOS filesystems;
• excludes .git and node_modules while walking the tree;
• reports each stale entry as .github/CODEOWNERS:<line>: <pattern> does not exist.

Bracket ranges are intentionally not classified as valid CODEOWNERS globs because GitHub CODEOWNERS does not support that gitignore feature.

Tests

Added five Node test-runner cases covering:

• existing root-relative files and directories;
• stale literal paths with accurate line numbers;
• supported glob skipping;
• unanchored literal names below the repository root;
• exact-case enforcement on case-insensitive filesystems.

The package-level check:codeowners command runs both the validator tests and validation of the real .github/CODEOWNERS file.

Validation completed:

• bun run check:codeowners — 5 passed, 0 failed; 11 literal paths checked and 1 glob skipped
• bun run check — all 13 checks passed