chore(agent): phase roadmap from TODO.md — 3 phases (138–140)

.agents/phases/todo/138_markdown_blockquotes/02_blockquote_css.md

@@ -0,0 +1,21 @@
+# Task 02 — `.md-quote` styling (theme-safe, WCAG AA)
+
+**Phase:** `138_markdown_blockquotes` · **Source:** `TODO.md:3` — "Markdown formatted ">" quotes aren't rendering"
+**Story:** n/a
+
+## Objective
+The blockquote is visually distinct and readable in all three rendering contexts (chat bubble, thinking block, document viewer) with ONE rule set, using only the existing `:root` palette.
+
+## Work
+1. `frontend/assets/styles.css` — add the `.md-quote` rule next to the other markdown element styles (the phase-44 `.md-table` / `.md-table-wrap` block is the anchor): `border-left: 3px solid <palette var>` (a visible-but-restrained border — pick from the existing `:root` palette, the executor's contrast judgment), `padding: 0.25rem 0.75rem`, `margin: 0.5rem 0`, `color: <muted palette var>` with a ≥4.5:1 contrast comment on the bubble surface per the house convention (`--ink-soft`'s `/* 8.2:1 on --surface */` qualifies — verify against the actual bubble background and document it).
+2. `frontend/assets/styles.css` — no background fill (ASSUMPTION A2); verify the rule renders acceptably in the chat `.bubble`, the `.thinking-text` block, and the document-viewer content region — add a scoped override only if the task-03 E2E proves a clash.
+- ASSUMPTION: the built-in dark palette is the single source of truth — the `:root`-drift unit test parses built-ins from this file, so no hex literal outside `:root` and no second copy.
+
+## Testing & Quality
+- Unit: `tests/unit/test_markdown_blockquotes.py` (task 03) source-pins the `.md-quote` rule's presence and its palette-var-only references (the phase-44 CSS-pin pattern).
+- Coverage: n/a (frontend).
+
+## Completion Criteria
+- [ ] the `.md-quote` rule exists in `styles.css`, references only `:root` palette vars, and carries a ≥4.5:1 contrast comment
+- [ ] the quote is visually distinct in chat + viewer (the E2E screenshot, task 03)
+- [ ] the theme no-op (B4) is unaffected — the rule uses existing vars; no new `ui_settings` column