docs: scrub gemini_cli references from 12 docs (provider count 8->7)
Cleaned: docs/guide_ai_client.md, docs/guide_architecture.md,
docs/guide_models.md, docs/guide_simulations.md,
docs/guide_context_aggregation.md, docs/guide_tools.md, docs/Readme.md,
conductor/tech-stack.md, conductor/product.md,
conductor/product-guidelines.md, conductor/workflow.md,
conductor/code_styleguides/error_handling.md.
Provider list citations updated to 7 (gemini, anthropic, deepseek,
minimax, qwen, grok, llama). guide_meta_boundary.md intentionally
retained (its gemini_cli references are the meta-tooling
GEMINI_CLI_HOOK_CONTEXT env var, NOT the provider; per spec GAP-A12).
ed
bd1d966c12