docs: explore-minimax memory + ask-minimax usage update

Add /explore-minimax and explore-minimax-run memory files, backfill
skill-ask-minimax / skill-ask-minimax-with-context entries, index them in
MEMORY.md. ask-minimax-usage.md gains the exploration use case and an
explicit no-secrets rule.

Claude-Session: https://claude.ai/code/session_01Ku87DDWwbJkTx6SuV3sQDc

MEMORY.md

@@ -14,6 +14,7 @@
 - [statusline](memory/script-statusline.md) — Status bar scripts: statusline.sh (renderer) and set-topic.sh (topic setter) for per-session topic display
 - [require-plan-file](memory/script-require-plan-file.md) — PreToolUse hook: blocks ExitPlanMode unless a *-PLAN.md file exists in the project root
 - [extract-transcripts](memory/script-extract-transcripts.md) — Manages transcript backup tracking: register, list, extract, mark-processed. Used by /log and pre-compact hook
+- [explore-minimax-run](memory/script-explore-minimax-run.md) — Hardened read-only MiniMax exploration wrapper: root scoping, secrets refusal, JSON answer channel, citation gate (lives in small-scripts)
 - [list-transcripts-here](memory/script-list-transcripts-here.md) — Wrapper calling extract-transcripts.py --list $(pwd); exists to avoid $() in SKILL.md bang commands
 
 ## Skills
@@ -30,6 +31,9 @@
 - [/orchestrate](memory/skill-orchestrate.md) — Check task state, launch container agents in git worktrees. Use `/loop 2m /orchestrate` for auto-polling
 - [/review-plan](memory/skill-review-plan.md) — Review plan against best practices (API, security, specs, TDD) before implementation
 - [/review-spec](memory/skill-review-spec.md) — Review spec for structure, requirement quality, security coverage, and testability
+- [/explore-minimax](memory/skill-explore-minimax.md) — Broad read-only codebase exploration in MiniMax M3 instead of an Anthropic Explore agent; cited conclusion only, Explore-agent fallback
+- [/ask-minimax](memory/skill-ask-minimax.md) — Delegate file-heavy tasks to a MiniMax M3 sub-session; only a concise result returns
+- [/ask-minimax-with-context](memory/skill-ask-minimax-with-context.md) — Bundle CONTEXT/CLAUDE.md hierarchy via shell redirects, then ask MiniMax a one-line question
 - [/spawn-session](memory/skill-spawn-session.md) — Spawn a new detached tmux Claude Code session with Remote Control, named after a project (wraps claude-tmux)
 
 ## References