docs: add Gemini CLI agents guide

[michaelxu2288]

What

Companion to scaleapi/scale-agentex-python#516 ("feat(harness): add a Gemini CLI harness"). Adds development_guides/gemini_cli_agents.md (CLI invocation with the prompt on argv and stdin closed, the stream-json to canonical-event mapping table, usage normalisation, the multi-turn caveat since --resume is index-based, tool approval modes), adds it to the Framework Agents nav, and lists Gemini CLI in the framework table and the coding-CLI bullet of Choose Your Agent Type.

Test

mkdocs build --strict with docs/requirements.txt: the page renders and its links resolve; no warnings reference the changed files (the 15 pre-existing strict-mode warnings are unrelated).

https://claude.ai/code/session_01HCVKnA7LeJZ44nxZz1uzF3

[greptile-apps]

Prompt Exposed in Arguments

Passing the potentially user-supplied prompt through -p puts its full contents in the subprocess argument list, where process listings or process telemetry may capture it. This is a non-blocking documentation concern: please warn readers not to include secrets and recommend suitable isolation or redaction for shared environments.

How this was verified: The documented command directly inserts prompt into the argument list passed to create_subprocess_exec.

Prompt To Fix With AI

This is a comment left during a code review.
Path: agentex/docs/docs/development_guides/gemini_cli_agents.md
Line: 16

Comment:
**Prompt Exposed in Arguments**

Passing the potentially user-supplied prompt through `-p` puts its full contents in the subprocess argument list, where process listings or process telemetry may capture it. This is a non-blocking documentation concern: please warn readers not to include secrets and recommend suitable isolation or redaction for shared environments.

**How this was verified:** The documented command directly inserts `prompt` into the argument list passed to `create_subprocess_exec`.

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

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