feat(gemini): add status / history / detail / read commands

[LeoLin990405]

ChatGPT and Claude already expose status / history / detail / read; Gemini was missing all four. The helpers needed to back them (getGeminiPageState, getGeminiConversationList, resolveGeminiConversationForQuery, getGeminiVisibleTurns) are already implemented in clis/gemini/utils.js — this PR is just the cli() wire-up plus an extractGeminiId parser shared between history and detail.

Commands added

Command	Source helper	Notes
gemini status	getGeminiPageState	Treats isSignedIn=null (composer present but no explicit Sign-in CTA) as logged in.
gemini history [--limit N]	getGeminiConversationList	Filters out the sidebar's "New chat" affordance (URL = /app, no id) so callers get a clean conversation list. --limit clamped to [1, 200].
gemini detail <id>	getGeminiConversationList + resolveGeminiConversationForQuery + getGeminiVisibleTurns	Accepts a bare 16-hex id, /app/<id> path, full URL, or a sidebar title (exact or substring).
gemini read	getGeminiVisibleTurns	Current-conversation turns.

detail only short-circuits the sidebar lookup when the input is unambiguously id-shaped (URL / /app/<id> / 16-hex bare id). Generic alphanumeric strings like "Empire study" go through title-matching first so a chat doesn't get treated as a literal conversation id.

Verification

• clis/gemini/commands.test.js — 18 cases:
  • 4× extractGeminiId (bare id / path / URL / garbage)
  • 3× status (connected / signed-out CTA / ambiguous-null treated as logged in)
  • 4× history (rows / --limit / --limit validation / empty sidebar)
  • 5× detail (direct-id nav / title resolution / missing id / no-match / zero turns)
  • 2× read (happy / zero turns)
• npm run test:adapter — 380 files / 3732 tests pass
• npm run build-manifest — clean, +4 entries (gemini/status, gemini/history, gemini/detail, gemini/read)

Live smoke test against a real signed-in Gemini account:

$ opencli gemini status
- Status: Connected   Login: Yes   Url: https://gemini.google.com/app

$ opencli gemini history --limit 5
- Index: 1   Id: b8368a89d4242e5f   Title: Gemini's New Features from I/O
              Url: https://gemini.google.com/app/b8368a89d4242e5f

$ opencli gemini detail b8368a89d4242e5f
- Index: 1   Role: User       Text: What's the latest with Gemini from Google I/O?
- Index: 2   Role: Assistant  Text: …

$ opencli gemini read
# same turns as detail, no navigation