v0.6.0 — Dream Stage 5: nightly context primer

Dream Stage 5: nightly context primer

Dream now closes each night by writing a short, self-overwriting "what's
still open" note into the host's persistent instructions file (e.g. Claude
Code's global CLAUDE.md), so a brand-new session starts oriented instead
of cold — it already has a glance at active threads and open commitments
before it ever calls memory_recall.

• New Stage 5 — "Prime": gathers tonight's consolidated entities plus
  any still-open commitment/plan/blocked observations (any age,
  unresolved), drafts at most 8 one-line bullets, and writes them into a
  guarded <!-- TARS:TODAY:START/END --> block. Full overwrite every
  night, never appended — resolved items just drop off.
• One narrow, deliberate exception to "brain over Markdown": this
  block is a disposable cache regenerated nightly purely to seed a fresh
  session's context — the brain remains the sole source of truth. Only
  the marked block is ever touched; nothing else in that file.
• Degrades quietly: skips the stage (never fails the run) if the
  target file is missing or unwritable.
• Generalized in the host-agnostic docs/routines/dream.md
  as an optional PRIMER_TARGET, for hosts that keep instructions in a
  file at all (skipped where instructions live in a UI field instead).

Docs-only release — no code or schema changes.