chore: switch to ruff + pydoclint, deprecate .gitingest, and perform a repo-wide quality sweep (#329)

* **Pre-commit**: replace `black` & `darglint` with `ruff-check` / `ruff-format`;
  add `pydoclint` for docstring quality
* **Deps**: drop `tomli`; tighten `typing_extensions`; add `eval-type-backport`;
  remove `black`, `djlint`, `pylint` from `requirements-dev`
* **Ignore files**: deprecate TOML-based `.gitingest`; introduce
  `.gitingestignore` (git-wildmatch, parsed via `_parse_ignore_file`)
* **Config**: new unified `[tool.ruff]` (lint + format + isort); delete
  `[tool.black]`, keep minimal `[tool.isort]` for now
* **Refactor/style**: adopt `from __future__ import annotations`, kw-only args,
  richer types; reorder params & `__all__`; move type-only imports under
  `if TYPE_CHECKING`; extract `_CLIArgs` `TypedDict`, migrate form data to
  `pydantic.QueryForm`; deduplicate `cli.main` / `_async_main`; use `pathlib`,
  avoid file-IO in async; replace magic numbers with constants; delete
  `is_text_file` (logic now lives in `FileSystemNode.content`)
* **Bug fix**: remove silent error in `notebook_utils._process_cell`
* **Docs**: refresh README badges
* **Tests**: update fixtures & assertions

**BREAKING**: new `.gitingestignore` file replaces (now-deprecated) `.gitingest`.

No functional API or CLI changes.

src/server/server_config.py

@@ -1,14 +1,19 @@
 """Configuration for the server."""
 
-from typing import Dict, List
+from __future__ import annotations
 
 from fastapi.templating import Jinja2Templates
 
 MAX_DISPLAY_SIZE: int = 300_000
-DELETE_REPO_AFTER: int = 60 * 60  # In seconds
+DELETE_REPO_AFTER: int = 60 * 60  # In seconds (1 hour)
 
+DEFAULT_FILE_SIZE_KB: int = 50  # Default maximum file size to include in the digest
 
-EXAMPLE_REPOS: List[Dict[str, str]] = [
+# Slider configuration (if updated, update the logSliderToSize function in src/static/js/utils.js)
+MAX_FILE_SIZE_KB: int = 100 * 1024  # 100 MB
+MAX_SLIDER_POSITION: int = 500  # Maximum slider position
+
+EXAMPLE_REPOS: list[dict[str, str]] = [
     {"name": "Gitingest", "url": "https://github.com/cyclotruc/gitingest"},
     {"name": "FastAPI", "url": "https://github.com/tiangolo/fastapi"},
     {"name": "Flask", "url": "https://github.com/pallets/flask"},