refactor(agents): migrate .agent/ planning tree to .agents/

Standardize on the .agents/ directory (shared with project skills):
phases/, user_stories/, reports/, screenshots/, validate.sh, and
phase-sessions/ + pipeline.log all move to .agents/ (git mv preserves
history; runtime artifacts move alongside).

Updates every reference in AGENTS.md, README.md, .gitignore, app
docstrings, and test story headers. Historical KB content in data/
and the runtime pipeline.log transcript are left untouched.

.agents/reports/07_story_responsive_polish.a1.md

@@ -0,0 +1,11 @@
+Phase 07 complete. Report:
+
+**Phase 07 — Responsive, Polished, Accessible UI: done. Committed `1b29b1c`, tree clean, pipeline empty (`todo/` → 0).**
+
+- **Fixed 4 real deviations found by the sweep:** (1) skip-link target `<main>` wasn't focusable → added `tabindex="-1"` on both pages; (2) `.composer textarea:focus { outline: none }` suppressed the `:focus-visible` ring → removed; (3) long unbreakable tokens blew out the chat column → `min-width: 0` on `.msg-body`/`.source-chip`; (4) deflection "Maybe try" chips (445px) overflowed 375px phones → `min-width:0; max-width:100%` on `.maybe-try .suggestion-chip` (text now wraps in-pill; onboarding scroll row untouched).
+- **New E2E suite** `tests/e2e/test_responsive_polish.py` — 7 tests (the 6 mapped + long-content): overflow-free at 360/375/768/1280/1600 both pages, 46rem centered cap at 1600, Sources table ≥80% width at 1280, landmarks/skip-link/labels/keyboard walk, computed WCAG contrast ≥4.5:1, reduced-motion, 60-char token wrap. **7/7 pass in isolation.**
+- **No-CDN re-verification** extended to `/sources.html` (integration test now parametrized over both pages).
+- **Whole repo green:** 124 passed, `app/` coverage **99%**, ruff clean, pyright 0 errors; all 7 E2E suites pass.
+- **Screenshots** (1280/1440/375, both pages, in `.agents/screenshots/`) reviewed against PLAN §7.1–7.4 — pass.
+- **README:** quickstart verified against real scripts/flags; "Updating the documents" now prominent (intro callout + TL;DR one-liner, "workflow you'll use most" lead, Sources-page verification step).
+- Phase file moved to `.agents/phases/complete/`; 05/06 moves recorded in the commit too.