Config: Add Additional path_filters to .coderabbit.yaml to Reduce Review Noise

## Overview

The current `.coderabbit.yaml` already excludes some paths from CodeRabbit reviews, but several common noise sources are not yet filtered. Adding more targeted `path_filters` will reduce unnecessary review churn on auto-generated, vendored, or non-reviewable files.

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## Proposed Change

Extend the `path_filters` section in `.coderabbit.yaml` with the following exclusions:

```yaml
path_filters:
# --- Minified / compiled assets ---
- "!**/*.min.js" # Minified JavaScript (not human-authored)
- "!**/*.min.css" # Minified CSS (not human-authored)
- "!**/*.bundle.js" # Bundled JS output
- "!**/*.map" # Source maps

# --- Vendored dependencies ---
- "!**/vendor/**" # Go vendor directory
- "!**/node_modules/**" # Node.js dependencies (usually already excluded)

# --- Database / ORM migration files ---
- "!**/migrations/**" # Auto-generated migration files (Django, Alembic, Flyway, etc.)
- "!**/db/schema.rb" # Rails auto-generated schema

# --- Python cache ---
- "!**/__pycache__/**" # Python bytecode cache
- "!**/*.pyc" # Compiled Python files
- "!**/*.pyo" # Optimized Python files

# --- Lockfiles ---
- "!**/poetry.lock" # Poetry lockfile
- "!**/Pipfile.lock" # Pipenv lockfile
- "!**/yarn.lock" # Yarn lockfile
- "!**/pnpm-lock.yaml" # pnpm lockfile
- "!**/Cargo.lock" # Rust lockfile (for non-library crates, review may be wanted)

# --- Generated / build artifacts ---
- "!**/dist/**" # Build output directories
- "!**/build/**" # Build output directories
- "!**/.next/**" # Next.js build output
- "!**/*.pb.go" # Protobuf-generated Go files
- "!**/*_generated.go" # Other Go generated files
- "!**/*.generated.ts" # Generated TypeScript files
```

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## Rationale

| Filter | Reason |
|---|---|
| Minified assets | Machine-generated; reviewing them adds no value |
| Vendor / node_modules | Third-party code; not owned by contributors |
| Migration files | Auto-generated by ORMs; schema intent is reviewed via model changes |
| Python cache | Binary/compiled; not reviewable |
| Lockfiles | Exact versions are managed by package managers; dependency changes are reviewed via manifest files |
| Build artifacts | Machine-generated output; not part of source authorship |
| Protobuf / generated files | Auto-generated from source specs; review the `.proto` or generator config instead |

---

## Acceptance Criteria

- [ ] `.coderabbit.yaml` updated with the additional `path_filters` entries.
- [ ] Verified that legitimate source files are not accidentally excluded.
- [ ] The `template-sync.yml` workflow propagates the updated config to child repos using this template.

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## References

- CodeRabbit path filters documentation: https://docs.coderabbit.ai/guides/review-instructions
- CodeRabbit YAML template reference: https://docs.coderabbit.ai/reference/yaml-template/