feat: Knowledge view + entity types (People, Places, Lists)

Data model:
- Migration 0036: adds note_type TEXT (default 'note') and metadata JSONB
  to the notes table; index on note_type
- Note model: entity_type property, note_type/metadata in to_dict()
- create_note() accepts note_type and metadata params

Backend:
- /api/knowledge — unified paginated endpoint: type/tag/sort/q filters,
  semantic search via embeddings, excludes tasks
- /api/knowledge/tags — distinct tags across knowledge objects
- New LLM tools: create_person, create_place, create_list, add_to_list,
  clear_checked_items — all wired into execute_tool()
- People and places auto-injected as compact summary into LLM system prompt

Frontend:
- KnowledgeView replaces HomeView at /; left filter panel (type+tag),
  toolbar (search, sort, graph toggle), card grid with type-aware cards
  (indigo=note, emerald=person, amber=place, sky=list), load-more pagination
- Today bar: upcoming events, overdue task count, Briefing/Chat links
- Floating mini-chat sticky to bottom: creates/continues a conversation
  inline, message history expands upward, close button ends session
- Graph panel: toggles as a 420px right panel at full viewport width
- AppHeader: Knowledge, Chat, Briefing, Calendar, Tasks, Projects
- Router: / → KnowledgeView; /knowledge redirect; HomeView import removed

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

src/fabledassistant/models/note.py

@@ -51,6 +51,10 @@ class Note(Base, TimestampMixin):
     recurrence_next_spawn_at: Mapped[datetime | None] = mapped_column(
         DateTime(timezone=True), nullable=True
     )
+    # Entity type — 'note' (default), 'person', 'place', 'list'
+    note_type: Mapped[str] = mapped_column(Text, default="note", server_default="note")
+    # Structured metadata for entity types (person/place/list)
+    metadata: Mapped[dict | None] = mapped_column(JSONB, nullable=True)
 
     __table_args__ = (
         Index("ix_notes_tags", "tags", postgresql_using="gin"),
@@ -59,12 +63,18 @@ class Note(Base, TimestampMixin):
         Index("ix_notes_user_id", "user_id"),
         Index("ix_notes_project_id", "project_id"),
         Index("ix_notes_milestone_id", "milestone_id"),
+        Index("ix_notes_note_type", "note_type"),
     )
 
     @property
     def is_task(self) -> bool:
         return self.status is not None
 
+    @property
+    def entity_type(self) -> str:
+        """Normalised type: 'note', 'person', 'place', or 'list'."""
+        return self.note_type or "note"
+
     def to_dict(self) -> dict:
         return {
             "id": self.id,
@@ -86,6 +96,8 @@ class Note(Base, TimestampMixin):
                 else None
             ),
             "is_task": self.is_task,
+            "note_type": self.entity_type,
+            "metadata": self.metadata or {},
             "created_at": self.created_at.isoformat(),
             "updated_at": self.updated_at.isoformat(),
         }