Pivot to text-first column-stack workspace + merge-with-review across AI artifacts

Workspace
- Pivot from "set of open panes" to a Finder-style miller column stack:
  TopBar / LeftSidebar / [section → entity → entity ...] / pinned text editor.
  openPanesStore is now an ordered Column[] with pushFrom / closeFrom /
  setStack; only one top-level section is rooted at a time.
- New entity column panes: Term, Block, Association, Constraint,
  Requirement, Finding. Click-through navigation truncates deeper
  columns automatically.
- LeftSidebar surfaces a pending-count chip per section (single-glance
  navigation cue) and spins its analyze ↻ via SVG Spinner whenever the
  LLM is working — including server-initiated runs caught by the runs
  poll, not just user-triggered ones.

Analyze pipeline + persistence
- Unified `concepts` pass (taxonomy + glossary in one LLM call) replaces
  the two-pass setup. Server still accepts ?section=taxonomy|glossary
  and normalizes them for back-compat.
- model / requirements / detection (assumptions, risks, inconsistencies)
  + cross-layer validation rules (X1–X4: stale term link, unlinked
  formalism, undefined linked term, prose-only term).
- Persistence: NarrativeDocument, ModelSnapshot, ChangelogEntry,
  TaxonomyTerm, RequirementEntry, Finding, AnalysisRun. Re-runs MERGE
  instead of replace: gentle update on existing items, suggested on new,
  deprecated on missing — same idiom for every artifact kind. User pins
  preserve "kept" decisions across re-analyses.
- Migrations: pivot_text_first, add_requirement_linked_term,
  term_review_state, review_state_for_reqs_and_findings,
  add_term_definition_pinned.

Concept ↔ ontology integration
- linkedTermId on Block / Association / Constraint / Requirement.
  PromoteToolbar lets the user formalize a concept inline: + Block /
  + Association / + Constraint / + Requirement, all routed through
  applyOps so undo/redo and SSE work for free.
- decideElement op for in-canvas keep/discard on review-pending model
  elements.

User-authored definitions
- TermColumn definition is click-to-edit. Save (Cmd-Enter / blur),
  Cancel (Esc), Reset to AI suggestion when pinned.
- definitionPinned flag on TaxonomyTerm: future Analyze runs leave the
  user's text alone. setTermDefinition repo function + POST
  /api/projects/[id]/terms/[termId]/definition endpoint.
- mergeTaxonomySuggestion + applyGlossaryDefinitions both pin-aware.

UX/UI
- StatusChip: single component for all state idioms (suggested,
  deprecated, accepted, dismissed, resolved, severity, validation code,
  confidence, warn). Replaces 5+ ad-hoc badge classes.
- PaneControls (PaneViewTabs + PaneFilterChip): separates view-mode
  toggles from filter chips so toggling Pending no longer flips you off
  the current view.
- PaneEmpty: unified empty-state with title + hint + action.
- PaneDrawer: collapsible groups for Pending / Discarded review; cards
  group as Kept (top) → Pending (bottom drawer) → Discarded (Findings
  only, hidden when empty). Restore action recovers dismissed/resolved
  findings.
- ConceptCard unifies Tree and A–Z views in Concepts; only Tree parents
  carry the chevron (no empty placeholder offset).
- Type + spacing tokens (--text-xs..xl, --space-1..6, --lh-tight/ui/
  prose, --radius-*) replace every ad-hoc value.
- Buttons standardized to body sans 500 (was a mishmash of mono / display).
- Card shells unified across Concepts / Requirements / Findings.

Cleanup
- Removed: LeftRail, FindingsPanel, IssuesPanel, SocratesDock,
  ProposalCard, SlashMenu, SlashExtension, slashSuggestion,
  CanvasHeader, TaxonomyPane, GlossaryPane, TermDetail (popover; now
  TermColumn).
- Section ids in openPanesStore: dropped taxonomy/glossary, added
  concepts. localStorage migration runs on hydrate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/components/editor/PaneControls.tsx

@@ -0,0 +1,97 @@
+// Shared pane-header controls. Two primitives:
+//
+//  - <PaneViewTabs/> — segmented control for VIEW MODES that are mutually
+//    exclusive (Tree | A–Z, Diagram | Summary). Always exactly one active.
+//
+//  - <PaneFilterChip/> — toggleable filter chip with an optional count pip.
+//    Use for filters like "Pending" that overlay the current view mode
+//    rather than replacing it. Disabled when count=0.
+//
+// The intent is to stop mixing "view mode" and "filter" in the same
+// pane-tabs cluster, which currently makes "Pending" feel like a third
+// view mode instead of a filter you can stack on Tree or A–Z.
+
+"use client";
+
+import type { ReactNode } from "react";
+
+// ─── PaneViewTabs ────────────────────────────────────────────────────────
+
+export interface PaneViewTab<V extends string> {
+  value: V;
+  label: ReactNode;
+  /** Optional tooltip. */
+  title?: string;
+}
+
+interface PaneViewTabsProps<V extends string> {
+  value: V;
+  onChange: (v: V) => void;
+  tabs: PaneViewTab<V>[];
+  /** ARIA label for the segmented group. */
+  ariaLabel?: string;
+}
+
+export function PaneViewTabs<V extends string>({
+  value,
+  onChange,
+  tabs,
+  ariaLabel = "View mode",
+}: PaneViewTabsProps<V>) {
+  return (
+    <div className="pane-view-tabs" role="tablist" aria-label={ariaLabel}>
+      {tabs.map(t => (
+        <button
+          key={t.value}
+          type="button"
+          role="tab"
+          aria-selected={value === t.value}
+          className={`pane-view-tab ${value === t.value ? "pane-view-tab-active" : ""}`}
+          onClick={() => onChange(t.value)}
+          title={t.title}
+        >
+          {t.label}
+        </button>
+      ))}
+    </div>
+  );
+}
+
+// ─── PaneFilterChip ──────────────────────────────────────────────────────
+
+interface PaneFilterChipProps {
+  /** Whether the filter is currently applied. */
+  active: boolean;
+  onToggle: () => void;
+  label: string;
+  /** Optional count to render as a pip (e.g. number of pending items).
+   *  When 0 (or undefined), the chip is disabled. */
+  count?: number;
+  title?: string;
+}
+
+export function PaneFilterChip({
+  active,
+  onToggle,
+  label,
+  count,
+  title,
+}: PaneFilterChipProps) {
+  const hasCount = typeof count === "number" && count > 0;
+  const disabled = typeof count === "number" && count === 0;
+  return (
+    <button
+      type="button"
+      className={`pane-filter-chip ${active ? "pane-filter-chip-active" : ""} ${
+        hasCount ? "pane-filter-chip-attention" : ""
+      }`}
+      onClick={onToggle}
+      title={title}
+      disabled={disabled}
+      aria-pressed={active}
+    >
+      <span className="pane-filter-chip-label">{label}</span>
+      {hasCount ? <span className="pane-filter-chip-pip">{count}</span> : null}
+    </button>
+  );
+}