hal0 v0.8.0-beta.3

Canonical LLM roles + Hindsight-native memory extraction
(ADR-0023). The two
canonical LLM roles are now agent (the capable default + fallback anchor,
replacing chat) and utility (the cheap helper, now seeded on every
install). chat and primary are retired as slot/role names.

Changed

• Canonical roles are agent + utility. agent replaces chat as the
  default/anchor everywhere (seeded slots, dispatch rule-9 fallback, the default
  pin set, _configured_primary). utility joins SEEDED_SLOTS so a fresh box
  never silently falls back to a heavy model for cheap extraction.
• Generalized virtual addressing. Any enabled type=llm slot X is now
  addressable as hal0/X (chain (X, agent)); the advertised canonical virtuals
  are hal0/agent, hal0/utility, hal0/npu.
• Memory graph extraction is operator-selectable and actually wired.
  [memory.graph].extraction_slot names the local llm slot Hindsight uses for
  graph extraction; hal0 propagates it to hindsight-api via a systemd drop-in
  (HINDSIGHT_API_LLM_MODEL=hal0/<slot>) + restart. hal0 memory graph enable
  takes --slot <name> (validated against the live enabled-llm-slot set).
• Cognee fully removed. The Cognee engine + wrapper are deleted; Hindsight is
  the platform engine (with a PgVector boot-degrade fallback). MemoryRecord
  survives as an alias of MemoryItem.

Breaking

• hal0/chat is no longer advertised. Clients pinned to hal0/chat (Hermes,
  OpenWebUI, any custom consumer) must repoint to hal0/agent.
  Hermes model.default is now hal0/agent.
• memory.graph.route / memory.graph.upstream removed, replaced by
  memory.graph.extraction_slot (default "utility"). Old route/upstream
  keys in hal0.toml are silently dropped on load (no hard-fail on upgrade). The
  hal0 memory graph enable --route/--provider/--model options are gone — use
  --slot.
• primary is no longer a slot alias. SLOT_ALIASES is {"agent-hermes": "agent"}.