ruamel.yaml has been showing signs of potential abandonment from PyPI
(see #1190). This commit replaces it with yamltrip, a Rust-backed
(tree-sitter-yaml) round-tripping YAML library that provides the same
comment- and formatting-preservation guarantees with better performance
and a smaller dependency footprint.

Key changes:

Dependency swap:
- Remove ruamel-yaml from project dependencies
- Add yamltrip>=0.2.0

Core YAML I/O rewrite (src/usethis/_file/yaml/io_.py):
- Rewrite YAMLFileManager to use yamltrip.Document internally
- Introduce YAMLDocument wrapper (replacing the raw ruamel
  CommentedMap/CommentedSeq)
- Add _upsert_safe() for robust scalar upserts handling empty
  documents, non-mapping routes, and exists_ok semantics
- Add _upsert_complex() for list/dict values using a document-rebuild
  approach (yamltrip only supports scalar upsert/replace natively)
- Add _serialize_yaml_value/_serialize_yaml_scalar helpers for
  producing valid block-style YAML from Python objects
- Handle flow-sequence fallback in extend_list when yamltrip cannot
  append to flow sequences (e.g. 'repos: []')

Pre-commit integration (src/usethis/_integrations/pre_commit/):
- Rewrite PreCommitConfigYAMLManager to use YAMLDocument
- Refactor remove_hook() to use surgical remove_from_list for whole-
  repo removal (preserves inline comments on sibling repos) and only
  falls back to full rebuild when hooks within a repo are modified
- Remove _pre_commit_fancy_dump (no longer needed; serialization is
  handled by the YAML I/O layer)

Deleted modules:
- src/usethis/_file/yaml/typing_.py (ruamel type aliases)
- src/usethis/_file/yaml/update.py (ruamel update helpers)
- tests/usethis/_file/yaml/test_update.py

Test migration:
- Rewrite all YAML I/O tests to use yamltrip assertions
- Update pre-commit tests (test_hooks.py, test_yaml.py) to use
  yamltrip.loads() and YAMLDocument semantics
- Relax exact-format assertions where the new serializer produces
  semantically equivalent but stylistically different output

Documentation:
- Update FAQ and pipeweld docs to reference yamltrip
- Regenerate functions.txt, module-tree.txt, AGENTS.md via hooks

Resolves #1190

Add explicit type arguments to dict and list parameters to satisfy
pyright reportMissingTypeArgument checks.

- Suppress unreachable code warning in fancy_model_dump else branch
- Add pyright: ignore for _FillValue type narrowing in zip_longest loop
- Fix dict type annotations in test references
- Remove unnecessary pyright ignore comments

Demonstrates that removing one hook from a multi-hook repo currently
loses inline comments due to the document-rebuild workaround. This test
will pass once yamltrip supports complex values in upsert/replace.

Tracks: usethis-python/yamltrip#18

The check-comment-keywords hook bans 'pragma:' in comments.

…ative complex values

yamltrip 0.3.0 adds native complex value support in upsert/replace and a
.root property. This eliminates ~130 lines of custom serialization code:
- Remove _upsert_complex, _deep_set, and all _serialize_yaml_* functions
- Replace doc[()] with doc.root throughout
- Add placeholder-then-replace pattern in _upsert_safe to force block-style
  output for new complex value keys
- Update test assertions for yamltrip's compact list indentation style
- Update xfail reason for partial hook removal test

- Add 13 new tests covering edge cases: scalar/empty root docs,
  regex keys, flow sequence fallback, complex values on empty docs
- Merge duplicate QueryError/PatchError handlers in __delitem__
  (prune_remove never raises QueryError with yamltrip)
- io_.py coverage: 87% -> 99% (1 defensive line remaining)

… dump

…ndles them natively