fix(ui-14): unify index.html <title> with manifest name — closes Finding #2

[VDP89]

Summary

• Closes Phase 4 dogfood Finding ci: add GitHub Actions workflow running pytest on push and PRs #2 (Cosmetic, Low). The PWA standalone window title bar rendered "Karasu UI" while the manifest identity (name + short_name) is sealed at "Karasu" per §3-A. Operator picked path 1 of the two paths offered in the dogfood log: unified identity, drop the "UI" suffix.
• One-line HTML change + lockstep test update + new cross-check test that pins the relationship for future PRs.

Files

• src/karasu/ui/static/index.html — <title>Karasu UI</title> → <title>Karasu</title>. The other static HTML titles (login.html, design-system.html, offline.html) were already consistent with the manifest convention; no ripple needed.
• tests/test_ui_server.py::test_index_html_served_at_root — existing route-wired assertion updated in lockstep.
• tests/test_ui_manifest.py::test_index_html_title_matches_manifest_name — NEW cross-check in the Layer 2 identity grouping that parses index.html, extracts the <title> content, and asserts it equals manifest["name"]. Same pattern as the existing test_tokens_css_bg_0_matches_manifest cross-check between tokens.css and the manifest.
• docs/phase-4-dogfood.md — Finding ci: add GitHub Actions workflow running pytest on push and PRs #2 marked resolved with path-1 rationale.

What's NOT in this PR

• Finding phase:1B real Claude smoke observations #4 (manifest screenshots[]) — operator decided to honor the original dogfood deferral. The shell empty-state is minimalist and the preview value in the install dialog is currently low; revisit when there are visuals worth showing.
• No brief amendment — UI-14 §3-A seals manifest fields but never sealed <title>. The cross-check test is the new binding.

Relation to other Phase 4 PRs

Independent of PR #116 (origin_matches), PR #117 (manifest id: "/"), and PR #118 (VAPID docs). The new INDEX_HTML_PATH constant in test_ui_manifest.py doesn't conflict with PR #117's Layer 2.5 grouping; landing order does not matter.

Test plan

• pytest tests/test_ui_manifest.py::test_index_html_title_matches_manifest_name — passes
• pytest tests/test_ui_server.py::test_index_html_served_at_root — passes
• Full file: 60/60 in tests/test_ui_manifest.py + tests/test_ui_server.py. One pre-existing Windows-only CRLF failure in test_valid_asset_under_static_dir_is_served is unrelated (also fails on main).
• After install, the OS title bar of the PWA standalone window should now read "Karasu" matching the launcher tile name.

🤖 Generated with Claude Code