fix: preserve distinct default configuration identities

[codeforester]

Summary

Use the collision-resistant application identity namespace for default user
configuration directories in both batteries-included entry points. Dotted
identities remain distinct, names that would collide after normalization receive
stable identity-specific components, and explicit user_config_dir values remain
authoritative.

The documentation records the path contract and explains that older normalized
directories are not moved, merged, or deleted automatically.

Issue

Fixes #425

Validation

• UV_CACHE_DIR=/private/tmp/base-cli-uv-cache uv run --extra dev --extra typer pytest -q (661 passed, 2 skipped)
• UV_CACHE_DIR=/private/tmp/base-cli-uv-cache uv run --extra quality mypy --strict lib/python/base_cli
• UV_CACHE_DIR=/private/tmp/base-cli-uv-cache uv run --extra quality ruff check lib/python/base_cli/paths.py lib/python/base_cli/config.py lib/python/base_cli/profile.py tests/test_paths.py tests/test_batteries_included_config.py
• git diff --check

Train

This car follows the v0.5.0 validation car for #424. It is based on that
branch so the two implementation changes can be reviewed and merged in order.

[codeforester]

Reviewed head f17e78c against #425. The dotted-identity bug is real and fixed: acme.tools previously collapsed to acme, and now gets its own directory. Explicit user_config_dir stays authoritative. Two blocking issues.

1. Every capitalized application name silently loses its existing user config. config_namespace_component reuses runtime_namespace_component, which lowercases names and appends a digest whenever the readable slug differs from the input. I compared the default directory on main and on this branch:

cli_name	main	this PR
basectl, mytool, gh-dash, my_tool	unchanged	unchanged
acme.tools	acme	acme.tools ✅ (the #425 fix)
MyTool	MyTool	mytool--0e6f80c36435
Base	Base	base--7b47361aad19
Alpha-Tool (already normalized)	Alpha-Tool	alpha-tool--dd7ba9aae023
AWSCLI	AWSCLI	awscli--597bec206248

After upgrading, an app named MyTool stops reading ~/.config/MyTool/config.yaml, with no warning. The docs say old directories aren't migrated, which satisfies #425's "do not silently move", but the user-visible result is silent config loss. #425 also asks for coverage of "ordinary existing names", and the only ordinary name tested is lowercase beta. Options:

• Keep the old directory when it's collision-free, and add a digest only for real collision cases (dots that used to be truncated, Alpha Tool vs Alpha-Tool).
• Or, when the legacy default_config_root() / normalize_cli_name(cli_name) exists and the new one doesn't, keep using the legacy directory or at least log a one-time warning naming both paths.

Either way, please add MyTool/Alpha-Tool to the tests and say which behavior is intended.

2. CI: Quality and security gates fails with ruff format: "File would be reformatted --> lib/python/base_cli/profile.py:235:41".

Minor: config_namespace_component is a pure alias of runtime_namespace_component. That's fine if it's meant as a seam for the config policy to diverge later (option 1 above would use exactly that), but say so in the docstring.

[codeforester]

Follow-up on the review findings:

• Preserved safe ordinary application identities such as MyTool and Alpha-Tool verbatim, avoiding silent config-directory changes; unsafe identities retain the slug-plus-digest fallback.
• Added regression coverage and documentation.
• Fixed the reported Ruff formatting failure.

Validation: 34 focused tests, strict mypy, Ruff check, Ruff format, and diff checks pass locally. The PR head is now 4862c5cc, based on updated #429.

[codeforester]

Re-verified at 4862c5c: fixed ✅. I compared default config directory names on main and this branch. Ordinary names are now preserved verbatim: MyTool, Base, Alpha-Tool, AWSCLI, my_tool, basectl. Only names that collided or were unsafe before get the slug-plus-digest: acme.tools/acme.deploy (both collapsed to acme on main), Alpha Tool (collided with Alpha-Tool), ../evil, a/b, .hidden. Nothing escapes the config root. The ruff format failure is fixed, and CI is green (95/95). Ready to merge once #429 lands (it's stacked on #429). Non-blocking: MyTool and mytool remain distinct identities that share one directory on case-insensitive filesystems (macOS), exactly as on main, so it's not a regression, but worth a sentence in docs/local-config.md.