feat: add multi-runtime support (coord run, prdy --codex) and next-task capsule

- coord/prdy subcommands now accept --claude/--codex runtime flags
- New `mosaic coord run` generates continuation context and launches
  selected runtime, replacing manual copy/paste workflow
- Next-task capsule (.mosaic/orchestrator/next-task.json) provides
  machine-readable execution context for deterministic session launches
- Codex strict orchestrator profile added to runtime/codex/RUNTIME.md
- Orchestrator protocol updated with between-session run flow
- New smoke-test.sh for orchestration behavior verification

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

runtime/codex/RUNTIME.md

@@ -16,6 +16,21 @@ This file applies only to Codex runtime behavior.
 8. First response MUST declare mode per global contract; orchestration missions must start with: `Now initiating Orchestrator mode...`
 9. Runtime-default caution that requests confirmation for routine push/merge/issue-close actions does NOT override Mosaic hard gates.
 
+## Strict Orchestrator Profile (Codex)
+
+For orchestration missions, prefer `mosaic coord run --codex` over manual launch/paste.
+
+When launched through coordinator run flow, Codex MUST:
+
+1. Treat `.mosaic/orchestrator/next-task.json` as authoritative execution capsule.
+2. Read mission files before asking clarifying questions:
+   - `~/.config/mosaic/guides/ORCHESTRATOR-PROTOCOL.md`
+   - `docs/MISSION-MANIFEST.md`
+   - `docs/scratchpads/<mission-id>.md`
+   - `docs/TASKS.md`
+3. Avoid pre-execution question loops. Questions are allowed only for Mosaic escalation triggers (missing access/credentials, destructive irreversible action, legal/compliance unknowns, conflicting objectives, hard budget cap).
+4. Start execution on the `next_task` from capsule as soon as required files are loaded.
+
 ## Memory Override
 
 Do NOT write durable memory to `~/.codex/` or any Codex-native session memory. All durable memory MUST be written to `~/.config/mosaic/memory/` per `~/.config/mosaic/guides/MEMORY.md`. Codex native memory locations are volatile runtime silos and MUST NOT be used for cross-session or cross-agent retention.