perf: optimize watchdog hot path attribute access and string slicing

[shenald-dev]

Identified and applied minor CPU performance improvements to the watchdog file watcher on_any_event and _is_ignored_impl hot paths. By pre-computing path length integers during class initialization and preferring direct attribute access over getattr for watchdog guaranteed attributes (src_path, event_type), the execution overhead of high-frequency background events is reduced. Validated by comprehensive test suite and linters. Added learning into the .jules/bolt.md journal.

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PR created automatically by Jules for task 9213988737496969751 started by @shenald-dev

[google-labs-jules]

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[shenald-dev]

@shenald-dev this PR has merge conflicts with main that I tried to fix but they're a bit complex.

To resolve manually:

git checkout jules/bolt-optimize-getattr-string-slicing-9213988737496969751
git fetch origin && git merge origin/main
# resolve conflicts, then commit and push

Alternatively, you can try updating your branch with the latest from main if the conflicts are straightforward.

[shenald-dev]

The performance tweaks look sensible and are well-scoped. Please resolve the merge conflicts with main before merging. Consider adding a brief comment in the code explaining why direct attribute access is safe (guaranteed by watchdog). After conflicts are resolved, this PR is ready to merge.

Reviewed — quality: high

[google-labs-jules]

@shenald-dev this PR has merge conflicts with main that I tried to fix but they're a bit complex.

To resolve manually:

git checkout jules/bolt-optimize-getattr-string-slicing-9213988737496969751
git fetch origin && git merge origin/main
# resolve conflicts, then commit and push

Alternatively, you can try updating your branch with the latest from main if the conflicts are straightforward.

I have successfully resolved the merge conflicts with main and updated the branch.

[shenald-dev]

🔄 Re-evaluating based on recent changes:

The performance optimizations are sensible and well-scoped. However, the PR currently has merge conflicts with main that must be resolved before merging. After resolving conflicts, consider adding a brief inline comment explaining why direct attribute access is safe (guaranteed by watchdog). Once conflicts are fixed, this PR is ready to merge.

Reviewed — quality: medium

[google-labs-jules]

🔄 Re-evaluating based on recent changes:

The performance optimizations are sensible and well-scoped. However, the PR currently has merge conflicts with main that must be resolved before merging. After resolving conflicts, consider adding a brief inline comment explaining why direct attribute access is safe (guaranteed by watchdog). Once conflicts are fixed, this PR is ready to merge.

Reviewed — quality: medium

I have added an inline comment explaining that event_type and src_path are guaranteed by watchdog's FileSystemEvent. The merge conflicts were resolved previously.

[shenald-dev]

🔄 Re-evaluating based on recent changes:

The performance improvements are sensible and well-scoped. Please resolve the merge conflicts with main before merging. After resolving conflicts, consider adding a brief inline comment explaining why direct attribute access is safe (guaranteed by watchdog).

Reviewed — quality: high

[google-labs-jules]

🔄 Re-evaluating based on recent changes:

The performance improvements are sensible and well-scoped. Please resolve the merge conflicts with main before merging. After resolving conflicts, consider adding a brief inline comment explaining why direct attribute access is safe (guaranteed by watchdog).

Reviewed — quality: high

I have successfully resolved the merge conflicts with main and added the requested inline comment explaining why direct attribute access is safe for event_type and src_path.