[backnotprop]

Adds an Antigravity CLI (agy) host to plannotator-tui last, so herdr-annotate's "review the agent's last reply" works on agy panes (plannotator/herdr-annotate#70).

Where it reads from

• App data directory: $ANTIGRAVITY_CLI_HOME, else ~/.gemini/antigravity-cli (%USERPROFILE% on Windows).
• Transcript: brain/<conversation id>/.system_generated/logs/transcript_full.jsonl. The truncated transcript.jsonl is never read.
• A reply is a PLANNER_RESPONSE step's non-empty content, read as-is. A step that only calls tools has no content and is skipped. Prompts (USER_INPUT) are not shown, so their <USER_REQUEST> and <ADDITIONAL_METADATA> wrappers are left in place. The picker's multi-reply review works like it does for other hosts. Each step's step_index is its message id.

How it picks the conversation

• Herdr reports agent: "agy" with agent_session {kind: id}. That id names the transcript directly. The new agy label is matched through Host::ALL, so the launcher needs no change apart from adding agy as a known process name.
• Without an id, the transcript does not record its folder, so two files supply it:
  • conversation_summaries.db: workspace_uris per conversation. It is opened read-only with the existing immutable fallback, and subagent rows are skipped.
  • history.jsonl: workspace plus conversationId for each prompt.
• A conversation whose workspace equals the cwd wins over one whose workspace only contains the cwd. Within each group, the newest transcript (by last write) that holds a message wins.
• If the database is missing or unreadable, the history decides alone. A transcript that neither file ties to the cwd is never shown. In that case the error names both files and the database failure.
• file:// URIs are percent-decoded, including Windows drive forms (file:///C:/..., file:///c%3A/...). On Windows, paths match regardless of case and slash direction.
• --session <transcript> detects the format without --host, and the conversation id is recovered from the path.

Verification

• Run against real agy 1.2.7 data on macOS (read-only):
  • by id;
  • by cwd through the database alone;
  • by cwd through the history alone;
  • a workspace subdirectory;
  • an unrelated folder (clear error).
• The fixture is built from the issue's sample with synthetic paths.
• Tests: 11 host tests (plus 1 Windows-only), plus detection, CLI end-to-end, and Herdr launch tests.
• cargo fmt --check, cargo clippy --workspace --all-targets -- -D warnings and cargo test --workspace (410 passed) are clean.

refs plannotator/herdr-annotate#70