Add lintrunner pre-commit hook

[abhinaykukkadapu]

Add lintrunner pre-commit hook

Summary:
Run lintrunner automatically on every commit via .githooks/pre-commit.
Hooks are enabled by default through install_executorch.sh.

Test Plan:

• lintrunner not installed: warns and skips
• .lintrunner.toml missing: warns and skips
• First init (no hash stored): runs lintrunner init, stores hash
• Second commit (toml unchanged): skips init
• .lintrunner.toml modified: re-runs init
• lintrunner init fails: blocks commit
• First commit (no HEAD^): runs without error
• Clean file: lint passes, commit succeeds
• Lint violation: lint fails, commit blocked
• sha256sum/shasum produce same hash

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/18689

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 6 New Failures, 4 Unrelated Failures

As of commit 298865a with merge base 1e9bd73 ():

NEW FAILURES - The following jobs have failed:

• pull / test-coreml-bc-macos (macos-m1-stable) / macos-job (gh)
  The process '/usr/bin/git' failed with exit code 1
• pull / unittest / macos / macos-job (gh)
  The process '/usr/bin/git' failed with exit code 1
• pull / unittest-buck / macos / macos-job (gh)
  The process '/usr/bin/git' failed with exit code 1
• pull / unittest-editable / macos / macos-job (gh)
  The process '/usr/bin/git' failed with exit code 1
• Test CoreML Backend / test-coreml / test-backend-macos (coreml, models) / macos-job (gh)
  No files were found with the provided path: /Users/ec2-user/runner/_work/_temp/artifacts/. No artifacts will be uploaded.
• Test CoreML Backend / test-coreml / test-backend-macos (coreml, operators) / macos-job (gh)
  No files were found with the provided path: /Users/ec2-user/runner/_work/_temp/artifacts/. No artifacts will be uploaded.

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• pull / test-custom-ops-linux / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Test QNN Backend / test-qnn / test-backend-linux (qnn, operators) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[github-actions]

This PR needs a release notes: label

If your change should be included in the release notes (i.e. would users of this library care about this change?), please use a label starting with release notes:. This helps us keep track and include your important work in the next release notes.

To add a label, you can comment to pytorchbot, for example
@pytorchbot label "release notes: none"

For more information, see
https://github.com/pytorch/pytorch/wiki/PyTorch-AutoLabel-Bot#why-categorize-for-release-notes-and-how-does-it-work.