feat: Human Mirror — GET /projects/{name}/mirror

Layer 3 of the AtoCore architecture. Generates a human-readable
project overview in markdown from structured data:

- Trusted Project State (by category)
- System Architecture (systems → subsystems → components with
  material and interface links)
- Decisions (with affected entities)
- Requirements & Constraints
- Materials
- Vendors
- Active Memories (with confidence and reference counts)

The mirror is DERIVED — every line traces back to an entity, state
entry, or memory. The footer stamps the generation timestamp and
the "not canonical truth" disclaimer.

API: GET /projects/{project_name}/mirror returns {project, format,
content} where content is the full markdown page. Supports project
aliases via resolve_project_name.

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

src/atocore/api/routes.py

@@ -30,6 +30,7 @@ from atocore.interactions.service import (
     list_interactions,
     record_interaction,
 )
+from atocore.engineering.mirror import generate_project_overview
 from atocore.engineering.service import (
     ENTITY_TYPES,
     RELATIONSHIP_TYPES,
@@ -1074,6 +1075,25 @@ def api_create_relationship(req: RelationshipCreateRequest) -> dict:
     }
 
 
+@router.get("/projects/{project_name}/mirror")
+def api_project_mirror(project_name: str) -> dict:
+    """Generate a human-readable project overview from structured data.
+
+    Layer 3 of the AtoCore architecture. The mirror is DERIVED from
+    entities, project state, and memories — it is not canonical truth.
+    Returns markdown that can be rendered, saved to a file, or served
+    as a dashboard page.
+    """
+    from atocore.projects.registry import resolve_project_name as _resolve
+
+    canonical = _resolve(project_name)
+    try:
+        markdown = generate_project_overview(canonical)
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=f"Mirror generation failed: {e}")
+    return {"project": canonical, "format": "markdown", "content": markdown}
+
+
 @router.get("/admin/backup/{stamp}/validate")
 def api_validate_backup(stamp: str) -> dict:
     """Validate that a previously created backup is structurally usable."""