feat: Centralized config output style system with --style flag

[tony]

Summary

• Add a centralized config output style system with three named styles: concise (flask: "git+url"), standard (flask: {repo: "git+url"}), and verbose (flask: {repo: url, vcs: git, remotes: {...}})
• Add --style CLI flag to fmt, add, discover, and import commands, with a settings.toml file for persistent defaults
• Replace all hardcoded {"repo": url} entry creation across four command families with a single format_repo_entry() API

Three config styles

Style	YAML example	Python type
concise	flask: "git+https://..."	str
standard	flask: {repo: "git+https://..."}	dict (repo key only)
verbose	flask: {repo: "git+url", vcs: "git", remotes: {origin: "..."}}	dict (repo + vcs + remotes)

Default: standard (preserves current behavior — no breaking changes).

New files

File	Purpose
src/vcspull/_internal/config_style.py	format_repo_entry(), restyle_repo_entry(), apply_config_style() + helpers
src/vcspull/_internal/settings.py	settings.toml loader with load_settings() / resolve_style()
tests/_internal/test_config_style.py	38 parametrized tests with syrupy snapshots
tests/_internal/test_settings.py	11 tests covering TOML parsing and style resolution

Key design decisions

1. Output-only concern — extract_repos() and validator.py already handle all three input forms; no changes needed there
2. Lossy conversion warning — converting verbose→concise with extra keys (remotes, shell_command_after) emits a warning and preserves the entry unchanged
3. Standard = current behavior — no existing functionality changes unless --style is explicitly passed or settings.toml is created
4. CLI overrides settings — --style flag beats settings.toml beats the built-in default

Commits (7 atomic)

1. feat(types[ConfigStyle]) — enum + type alias
2. feat(_internal[config_style]) — central formatting module + tests
3. feat(_internal[settings]) — TOML settings + tomli dep + tests
4. feat(cli/fmt[style]) — --style flag for bidirectional restyling
5. feat(cli/add[style]) — format_repo_entry() with --style
6. feat(cli/discover[style]) — format_repo_entry() with --style + cli dispatch
7. feat(cli/import[style]) — format_repo_entry() with --style across 6 service handlers

Test plan

• 1066 tests pass (51 new + 1015 existing)
• uv run ruff check . clean
• uv run ruff format --check . clean
• uv run mypy clean (0 errors in 92 source files)
• Manual: vcspull fmt --style concise --write converts dict entries to strings
• Manual: vcspull fmt --style verbose --write converts string entries to dicts with remotes
• Manual: vcspull add ./some-repo --style concise writes string entry
• Manual: vcspull discover ~/code --style verbose --dry-run shows verbose entries
• Manual: Create ~/.config/vcspull/settings.toml with config_style = "concise", verify default

[codecov]

Codecov Report

❌ Patch coverage is 85.35032% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.36%. Comparing base (e6a62d9) to head (472746a).

Files with missing lines	Patch %	Lines
src/vcspull/_internal/config_style.py	80.61%	13 Missing and 6 partials ⚠️
src/vcspull/_internal/settings.py	95.34%	2 Missing ⚠️
src/vcspull/cli/fmt.py	80.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #516      +/-   ##
==========================================
+ Coverage   83.30%   83.36%   +0.06%     
==========================================
  Files          32       34       +2     
  Lines        4492     4647     +155     
  Branches      903      937      +34     
==========================================
+ Hits         3742     3874     +132     
- Misses        499      515      +16     
- Partials      251      258       +7     

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[tony]

Re-authored on current master. The three infrastructure commits (ConfigStyle/RawRepoEntry types, the central config_style formatter, and the settings loader with their tests) cherry-picked cleanly. The CLI wiring was rebuilt against master's current handlers rather than the stale versions the branch carried.

Landed: the flagship vcspull fmt --style {concise,standard,verbose}, threaded through format_config_file → format_single_config → format_config onto master's _classify_fmt_action flow (keeping save_config, not the branch's save_config_yaml). Restyling fires only on an explicit --style, so plain vcspull fmt is unchanged.

Deferred: styling newly-added entries in add/discover/import. Those handlers were each rebuilt around pinning (build_repo_entry, the _classify_* action enums, --prune-untracked) since this branch was authored, so wiring format_repo_entry into them is a separate, larger integration best done as a focused follow-up now that the ConfigStyle/config_style/settings infrastructure is in place. The full gate (ruff/mypy/pytest/build-docs) is green.