feat(workplans): CUST-WP-0018/0019/0020 — API hardening, dashboard UX polish, test suite

Consolidates all open technical debt into three workplans:
- CUST-WP-0018: API hardening & code quality (TD-006–019 medium/high items)
- CUST-WP-0019: Dashboard UX polish (Repos nav restructure, config.js cleanup,
  todo filter fix for new suggestion workflow statuses)
- CUST-WP-0020: pytest test suite with real DB (TD-014)

Also fixes todo.md Suggestions filter: was checking status===open but new
suggestions enter with status=submitted; now excludes terminal statuses only.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dashboard/src/todo.md

@@ -38,7 +38,8 @@ const todoState = (async function*() {
           domain:           wsMap[t.workstream_id]?.domain ?? "unknown",
         }));
         contribs = contribList;
-        improvements = ri.ok ? (await ri.json()).filter(t => t.debt_type === "dashboard-improvement" && t.status === "open") : [];
+        const CLOSED = new Set(["finished", "wont_fix", "resolved", "deferred"]);
+        improvements = ri.ok ? (await ri.json()).filter(t => t.debt_type === "dashboard-improvement" && !CLOSED.has(t.status)) : [];
       }
     } catch {}
     yield {tasks, contribs, improvements, ok, ts: new Date()};