Loki Mode

Reuse done-recognition: a no-PRD reuse run no longer rebuilds finished work

• The bug: a loki start with NO PRD over a project Loki already built and
  completed reverse-engineered (reused) the prior generated PRD and then rebuilt
  a full task queue and re-ran the RARV loop, re-doing finished work. The reuse
  path never asked "is this reused PRD already satisfied by the current code?"
  Observed live: a completed project (completion signal present, all tests green,
  advisor said stop) still got an 11-task prd-* queue and fresh iterations.
• The fix: a single localized gate (reuse_done_recognition_gate, in the new
  autonomy/lib/done-recognition.sh) runs in run_autonomous() between
  load_state and the queue/loop, only on a no-PRD reuse of an existing
  generated PRD. It model-verifies whether the codebase already satisfies the
  spec and routes to one of three outcomes:
  • done: re-runs the tests now, re-checks each requirement, refreshes the
    verified-completion record, finishes through the normal completion path, and
    tells the user clearly ("This project already satisfies its spec ... To
    rebuild from scratch run loki start --fresh-prd; to extend it, edit the
    spec or pass a new/changed PRD."). No wasted iterations, no stray delegate
    branch (the gate runs before the start-sha/delegate block).
  • incomplete: writes a prd_sha-guarded satisfied-requirements manifest so
    populate_prd_queue builds ONLY the unsatisfied requirements (no full
    replan).
  • inconclusive: falls through to the normal full build (safe default).
• Trust moat intact (no fake-green): the positive done verdict is always
  the model's, grounded in re-run reality, never asserted from a stale artifact.
  A model done is DOWNGRADED to build if the fresh test-results.json is red or
  any requirement is unmet/uncertain. The update action (PRD stale by
  definition) may never fast-stop as done; it only feeds the incremental queue.
  The only deterministic shortcut is NEGATIVE (cheap signals that route to
  BUILD, e.g. no completion footprint at all, or a provider that cannot verify).
• Rollout: DEFAULT-ON. LOKI_DONE_RECOGNITION=0 disables the gate (legacy
  reuse-then-build behavior). Trust-safe because any uncertainty falls through to
  build, so the worst case is today's behavior.
• Tests: tests/test-reuse-done-recognition.sh (registered in
  tests/run-all-tests.sh and scripts/local-ci.sh) exercises the gate with a
  stubbed model seam across done+green, done+red-downgrade, inconclusive,
  incremental-only-unsatisfied, opt-out, update-never-fast-stops, the negative
  fast-paths, and a static no-emoji/no-em-dash scan.