fix: release v0.16.3 hotfixes

chore(release): prepare v0.16.2

Bumps from v0.16.1.

- #118 (kdramapulse): wire injection_prompt in async inter-agent
  result delivery — sub-agent responses now correctly route through
  the parent session instead of being delivered raw.
- Internal cleanup: shared injection-prompt builder; fixed Matrix
  session-continuation hint that was missing its middle clause.
- #117 (Ilinvic): Codex turn.failed errors (e.g. usage limit reached)
  now surface the real cause from the stream instead of the misleading
  "thread … not found" stderr artefact. Rate-limit hint also fires for
  Codex's wording ("usage limit", "upgrade to pro").

Release v0.16.0

chore: bump version to 0.15.0

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

chore: bump version to 0.14.0

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

chore: bump version to 0.13.0

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

chore: bump version to 0.12.0

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

chore: bump version to 0.11.0

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