docs: prose pass, string-injection validation fix, refreshed social card

[lesnik512]

Summary

Prose pass over README.md and the published docs, plus a fix for a self-contradiction in the string-injection page and a refreshed social card.

Changes

• Dashes: 18 em/en dashes in prose replaced with commas, colons, or periods (0 left).

• Bold run-in labels: 30 removed (46 to 16). The FastAPI tips list, the Singleton concurrency list, the Resource method bullets, and the factories .provider bullets became plain sentences; the injection FAQ became one heading per question (this also fixes item 2, which was indented under item 1); **Example:**, **Note:**, and **Setup:** labels became plain lead-ins. The 16 left are all in docs/agents/issue-tracker.md, which is agent configuration (not in nav) and skipped on purpose.

• Headings: 86 renamed to sentence case or stripped of bold, across docs and migration guides. The anchors other pages link to (#using-a-custom-router-class, #quick-reference, #named-scopes-with-the-inject-wrapper, #changes-to-naming-of-methods) keep their slugs.

• Contrasts, filler, and staging: removed "simply", "In essence", "might seem complex at first glance", a restating closer in generator-injection, and Per default (now "By default"). Also fixed small grammar slips (as following, an StateNotInitializedError, last initialize value, chooses between provider).

• The FastAPI tip that pointed to the "container connection" docs now links to the multiple-containers page.

• String injection: the page said both that Provide["..."] validates the string immediately and that container and provider names are only checked at call time. Run against this branch:

  • Provide["NoDots"] and Provide["A..b"] raise ValueError: Invalid provider definition immediately (format check in StringProviderDefinition.__init__).
  • @inject on Provide["Ghost.p"] (unknown container) decorates without error; calling it raises ValueError: Container Ghost not found in scope!.
  • Provide["Known.missing"] (unknown provider on a known container) also decorates without error; calling it raises ValueError: Provider missing not found in container Known.

  Both places now say that only the format is checked up front and the names are checked at call time.

• docs/assets/social-card.png is replaced with the card regenerated from the current description in docs: sync social-card taglines with repo descriptions .github#125 (blob 9569337 on .github main).

Checklist

• Lint and format pass (ruff)
• Type check passes (mypy and pyrefly)
• Tests pass and new behavior is covered (458 passed; docs only)
• Build succeeds (uv build) if packaging or build config changed
• Docs updated if behavior or public API changed (mkdocs build --strict passes)
• Repo metadata stays consistent across the three surfaces (GitHub description, pyproject description, profile blurb) if this touches packaging

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.