fix: restore Gemini async completion flow (hash/autostart/req_id compat)

[bookandlover]

Problem

Recent Gemini workflow regressions observed in CCB:

1. ask gemini can fail or hang in mixed Gemini project layouts.
2. Gemini may finish, but caller side stays in "processing" and does not reliably collect completion.

Root Causes Addressed

• Project session discovery did not robustly handle Gemini slug-based directories with collision suffixes (for example claude-code-bridge-1).
• DONE marker matching in protocol adapters did not fully cover the current req_id format (YYYYMMDD-HHMMSS-mmm-PID-counter).
• Connectivity checks/autostart could run under caller cwd instead of target project cwd in some paths.
• Unified askd readiness was not checked early enough for async paths.

Changes

• lib/gemini_comm.py

  • Add project-hash candidate discovery for slug + suffixed slug + legacy SHA layouts.
  • Prefer active/recent candidates and keep known hashes for reader continuity.

• lib/gaskd_protocol.py

• lib/daskd_protocol.py

  • Expand ANY_DONE_LINE_RE to accept req_id with trailing counter.

• bin/ccb-ping

  • Add --autostart.
  • Resolve work dir from --session-file to ensure daemon checks/start happen in target project context.

• bin/ccb-mounted

  • Add argument parsing for --json | --simple | --autostart [path].
  • Execute mounted checks against provided project path (not implicit caller cwd).

• bin/ask

  • Add unified askd readiness/autostart check before async submission and unified send path.

Validation

Added tests:

• test/test_gemini_comm.py
• test/test_autostart_on_check.py
• test/test_ask_cli.py

Local verification:

• pytest -q test/test_gemini_comm.py test/test_autostart_on_check.py test/test_ask_cli.py
• python -m compileall -q lib bin ccb

Compatibility / Risk

• Scope is limited to Gemini path/session discovery, completion marker compatibility, and autostart routing.
• Preserves compatibility with legacy SHA-based Gemini layout while supporting current slug-based layouts.
• No behavior change intended for unrelated providers beyond shared daemon readiness guard.