chore(web): stop tracking Next build output and enforce repo hygiene

[evan188199-tech]

Description

Stops tracking the generated web/.next-deeptutor tree and adds guardrails that keep regenerated artifacts out of Git.

• Removes the tracked Next build output from the index while retaining the custom build directory at runtime.
• Adds a repository hygiene check for tracked build outputs, caches, reports, and common generated artifacts.
• Runs repository/workspace hygiene in CI for pushes and PRs targeting main or dev.
• Runs repository hygiene from pre-commit and explains the clean primary-checkout / feature-worktree workflow in CONTRIBUTING.md.
• Adds a dependency-free local pre-commit hook that also blocks accidental direct commits on main unless explicitly allowed.
• Updates the web build wrapper to regenerate required checked-in inputs while restoring them after build.
• Adds tests for workspace hygiene, branch policy, wrapper routing, and restoration behavior.

This also removes the repository-wide pre-commit blocker reported on #728: formatting hooks currently attempt to rewrite tracked Next build files, so contributors cannot run pre-commit run --all-files successfully.

Related Issues

• Related to feat: add Spanish localization and language-aware prompts #728

Module(s) Affected

• agents
• api
• config
• core
• knowledge
• logging
• services
• tools
• utils
• web (Frontend)
• docs (Documentation)
• scripts (Scripts)
• tests (Tests)
• Other: ...

Checklist

• I have read and followed the contribution guidelines.
• My code follows the project's coding standards.
• I have run pre-commit run --all-files and fixed any issues.
• I have added relevant tests for my changes.
• I have updated the documentation (if necessary).
• My changes do not introduce any new security vulnerabilities.

Validation

• python scripts/check_repo_hygiene.py: PASS
• python scripts/check_workspace_hygiene.py: PASS
• python -m pytest tests/scripts/test_branch_policy.py tests/scripts/test_workspace_hygiene.py: 6 passed
• python -m ruff check changed Python scripts/tests: PASS
• python -m ruff format --check changed Python scripts/tests: PASS
• .github/workflows/repository-hygiene.yml YAML parse: PASS
• git diff --check: PASS
• npm run test:node: 412 passed, 1 pre-existing failure (ordinary users can edit only their owner-scoped Codex reasoning overrides), reproduced on unmodified origin/dev
• npm run lint: PASS, 56 pre-existing warnings
• npm run build: PASS
• git status --short after build: clean
• Full repository pre-commit was not run in this local environment; the changed-file checks above all passed.