feat: Phase 6 — Living Taxonomy + Universal Capture

Closes two real-use gaps:
1. "APM tool" gap: work done outside Claude Code (desktop, web, phone,
   other machine) was invisible to AtoCore.
2. Project discovery gap: manual JSON-file edits required to promote
   an emerging theme to a first-class project.

B — atocore_remember MCP tool (scripts/atocore_mcp.py):
- New MCP tool for universal capture from any MCP-aware client
  (Claude Desktop, Code, Cursor, Zed, Windsurf, etc.)
- Accepts content (required) + memory_type/project/confidence/
  valid_until/domain_tags (all optional with sensible defaults)
- Creates a candidate memory, goes through the existing 3-tier triage
  (no bypass — the quality gate catches noise)
- Detailed tool description guides Claude on when to invoke: "remember
  this", "save that for later", "don't lose this fact"
- Total tools exposed by MCP server: 14 → 15

C.1 Emerging-concepts detector (scripts/detect_emerging.py):
- Nightly scan of active + candidate memories for:
  * Unregistered project names with ≥3 memory occurrences
  * Top 20 domain_tags by frequency (emerging categories)
  * Active memories with reference_count ≥ 5 + valid_until set
    (reinforced transients — candidates for extension)
- Writes findings to atocore/proposals/* project state entries
- Emits "warning" alert via Phase 4 framework the FIRST time a new
  project crosses the 5-memory alert threshold (avoids spam)
- Configurable via env vars: ATOCORE_EMERGING_PROJECT_MIN (default 3),
  ATOCORE_EMERGING_ALERT_THRESHOLD (default 5), TOP_TAGS_LIMIT (20)

C.2 Registration surface (src/atocore/api/routes.py + wiki.py):
- POST /admin/projects/register-emerging — one-click register with
  sensible defaults (ingest_roots auto-filled with
  vault:incoming/projects/<id>/ convention). Clears the proposal
  from the dashboard list on success.
- Dashboard /admin/dashboard: new "proposals" section with
  unregistered_projects + emerging_categories + reinforced_transients.
- Wiki homepage: "📋 Emerging" section rendering each unregistered
  project as a card with count + 2 sample memory previews + inline
  "📌 Register as project" button that calls the endpoint via fetch,
  reloads the page on success.

C.3 Transient-to-durable extension
(src/atocore/memory/service.py + API + cron):
- New extend_reinforced_valid_until() function — scans active memories
  with valid_until in the next 30 days and reference_count ≥ 5.
  Extends expiry by 90 days. If reference_count ≥ 10, clears expiry
  entirely (makes permanent). Writes audit rows via the Phase 4
  memory_audit framework with actor="transient-to-durable".
- POST /admin/memory/extend-reinforced — API wrapper for cron.
- Matches the user's intuition: "something transient becomes important
  if you keep coming back to it".

Nightly cron (deploy/dalidou/batch-extract.sh):
- Step F2: detect_emerging.py (after F pipeline summary)
- Step F3: /admin/memory/extend-reinforced (before integrity check)
- Both fail-open; errors don't break the pipeline.

Tests: 366 → 374 (+8 for Phase 6):
- 6 tests for extend_reinforced_valid_until covering:
  extension path, permanent path, skip far-future, skip low-refs,
  skip permanent memories, audit row write
- 2 smoke tests for the detector (imports cleanly, handles empty DB)
- MCP tool changes don't need new tests — the wrapper is pure passthrough

Design decisions documented in plan file:
- atocore_remember deliberately doesn't bypass triage (quality gate)
- Detector is passive (surfaces proposals) not active (auto-registers)
- Sensible ingest-root defaults ("vault:incoming/projects/<id>/")
  so registration is one-click with no file-path thinking
- Extension adds 90 days rather than clearing expiry (gradual
  permanence earned through sustained reinforcement)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/atocore/engineering/wiki.py

@@ -116,6 +116,40 @@ def render_homepage() -> str:
             lines.append('</a>')
         lines.append('</div>')
 
+    # Phase 6 C.2: Emerging projects section
+    try:
+        import json as _json
+        emerging_projects = []
+        state_entries = get_state("atocore")
+        for e in state_entries:
+            if e.category == "proposals" and e.key == "unregistered_projects":
+                try:
+                    emerging_projects = _json.loads(e.value)
+                except Exception:
+                    emerging_projects = []
+                break
+        if emerging_projects:
+            lines.append('<h2>📋 Emerging</h2>')
+            lines.append('<p class="emerging-intro">Projects that appear in memories but aren\'t yet registered. '
+                         'One click to promote them to first-class projects.</p>')
+            lines.append('<div class="emerging-grid">')
+            for ep in emerging_projects[:10]:
+                name = ep.get("project", "?")
+                count = ep.get("count", 0)
+                samples = ep.get("sample_contents", [])
+                samples_html = "".join(f'<li>{s[:120]}</li>' for s in samples[:2])
+                lines.append(
+                    f'<div class="emerging-card">'
+                    f'<h3>{name}</h3>'
+                    f'<div class="emerging-count">{count} memories</div>'
+                    f'<ul class="emerging-samples">{samples_html}</ul>'
+                    f'<button class="btn-register-emerging" onclick="registerEmerging({name!r})">📌 Register as project</button>'
+                    f'</div>'
+                )
+            lines.append('</div>')
+    except Exception:
+        pass
+
     # Quick stats
     all_entities = get_entities(limit=500)
     all_memories = get_memories(active_only=True, limit=500)
@@ -324,7 +358,41 @@ _TEMPLATE = """<!DOCTYPE html>
   .tag-badge:hover { opacity: 0.85; text-decoration: none; }
   .mem-expiry { font-size: 0.75rem; color: #d97706; font-style: italic; margin-left: 0.4rem; }
   @media (prefers-color-scheme: dark) { .mem-expiry { color: #fbbf24; } }
+  /* Phase 6 C.2 — Emerging projects section */
+  .emerging-intro { font-size: 0.9rem; opacity: 0.75; margin-bottom: 0.8rem; }
+  .emerging-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1rem; margin-bottom: 1rem; }
+  .emerging-card { background: var(--card); border: 1px dashed var(--accent); border-radius: 8px; padding: 1rem; }
+  .emerging-card h3 { margin: 0 0 0.3rem 0; color: var(--accent); font-family: monospace; font-size: 1rem; }
+  .emerging-count { font-size: 0.8rem; opacity: 0.6; margin-bottom: 0.5rem; }
+  .emerging-samples { font-size: 0.85rem; margin: 0.5rem 0; padding-left: 1.2rem; opacity: 0.8; }
+  .emerging-samples li { margin-bottom: 0.25rem; }
+  .btn-register-emerging { width: 100%; padding: 0.45rem 0.9rem; background: var(--accent); color: white; border: 1px solid var(--accent); border-radius: 4px; cursor: pointer; font-size: 0.88rem; font-weight: 500; margin-top: 0.5rem; }
+  .btn-register-emerging:hover { opacity: 0.9; }
 </style>
+<script>
+async function registerEmerging(projectId) {
+  if (!confirm(`Register "${projectId}" as a first-class project?\n\nThis creates:\n• /wiki/projects/${projectId} page\n• System map + gaps + killer queries\n• Triage + graduation support\n\nIngest root defaults to vault:incoming/projects/${projectId}/`)) {
+    return;
+  }
+  try {
+    const r = await fetch('/admin/projects/register-emerging', {
+      method: 'POST',
+      headers: {'Content-Type': 'application/json'},
+      body: JSON.stringify({project_id: projectId}),
+    });
+    if (r.ok) {
+      const data = await r.json();
+      alert(data.message || `Registered ${projectId}`);
+      window.location.reload();
+    } else {
+      const err = await r.text();
+      alert(`Registration failed: ${r.status}\n${err.substring(0, 300)}`);
+    }
+  } catch (e) {
+    alert(`Network error: ${e.message}`);
+  }
+}
+</script>
 </head>
 <body>
 {{nav}}