feat(context): reasoning-thread continuity, L3 doc filtering, and gate hardening

Threads reasoning_content across inference calls and journal renders, filters
markdown noise out of L3 repo-knowledge retrieval, adds PlanLinter H3 checks,
and tightens filesystem tool output/dir-listing behavior surfaced by prior
live QA (see project_readloop_campaign memory).

docs/ui/web-ui-design-spec.md

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+# Web UI Design Specification
+
+## Aesthetic
+- **Theme**: Soft Rounded + Blue Accent.
+- **Consistency**: Should align with the TUI layout plan.
+
+## Layout
+- **Sidebar**: Centralized navigation.
+- **Main Area**: Dynamic content based on selection.
+- **Event Log**: Easily accessible (Source of Truth).
+
+## Components
+- **Cards**: For task summaries, status updates.
+- **Badges**: For status (e.g., `CLAIMED`, `PENDING`, `COMPLETED`).
+- **Progress Bars**: For multi-step task progress.
+- **Service Layer**: Placeholders for `apps/server` endpoints.
+
+## UX Priorities
+- Clear hierarchy.
+- Intuitive navigation.
+- Avoid clutter (maintain information density).