feat(dashboard): nav restructure, full context-help coverage, 11 new ref docs

Navigation:
- New order: Overview · Todo · Domains · Repos · Workstreams (collapsible,
  open:false, with atomic sub-entries: Decisions, Tasks, Debt, Extends,
  Dependencies) · Contributions · SBOM · Progress · Reference (collapsible)
- Reference section gains path:/reference landing page; all 18 doc pages
  listed in nav (alphabetical) and in reference.md table

New pages:
- todo.md — Internal / Ecosystem / Third-party todo classification
- dependencies.md — dependency edge table derived from state/summary
- reference.md — Reference landing page with full doc index

New reference doc pages (11):
  contributions, debt, dependencies, domains, extensions, overview,
  repos, tasks, todo + reference (meta) already added previously

doc-overlay.js — lazy bubblehelp tooltip:
- _titleCache Map + _fetchDocTitle(docPath): on first hover of any ?
  button, fetches the target doc page, parses <h1>, sets btn.title
- Native browser tooltip appears exactly on the ? circle on subsequent hover

Context-help wired on all 14 dashboard pages:
- h1 withDocHelp added to: index, todo, domains, repos, tasks, techdept,
  extensions, dependencies (contributions/workstreams/decisions/sbom/
  progress/reference were already wired)
- domains.md + repos.md: added missing withDocHelp import and live-data link
- tasks/techdept/extensions: removed duplicate _h1 const that caused
  SyntaxError: Identifier '_h1' has already been declared

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

dashboard/src/domains.md

@@ -38,6 +38,7 @@ const _ts     = domainsState.ts;
 
 ```js
 import {injectTocTop} from "./components/toc-sidebar.js";
+import {withDocHelp}  from "./components/doc-overlay.js";
 import {openEntityModal} from "./components/entity-modal.js";
 
 // ── Live indicator ─────────────────────────────────────────────────────────────
@@ -47,8 +48,12 @@ const _liveEl = html`<div class="live-indicator">
     ? `Live · updated ${_ts?.toLocaleTimeString()}`
     : html`<span style="color:red">Offline — run: <code>make api</code></span>`}
 </div>`;
+withDocHelp(_liveEl, "/docs/live-data");
 injectTocTop("live-indicator", _liveEl);
 
+const _h1 = document.querySelector("#observablehq-main h1");
+if (_h1) { _h1.style.position = "relative"; withDocHelp(_h1, "/docs/domains"); }
+
 // ── KPI row ────────────────────────────────────────────────────────────────────
 const activeDomains = domains.filter(d => d.status === "active");
 const archivedDomains = domains.filter(d => d.status === "archived");