Phase B: config-file refs + per-platform tool refs + spec

Two structural changes:

1. Generalize CLAUDE.md-specific guidance:
   - "Project-specific conventions (put in CLAUDE.md)" → "(put in
     your instructions file)" in writing-skills/SKILL.md
   - "(explicit CLAUDE.md violation)" → "(explicit instruction-file
     violation)" in receiving-code-review/SKILL.md
   - The instruction-priority list in using-superpowers/SKILL.md
     stays inclusive (CLAUDE.md, GEMINI.md, AGENTS.md) — that's
     load-bearing, not a substitution opportunity.

2. Per-platform tool reference files at skills/using-superpowers/
   references/{claude-code,codex,copilot,gemini}-tools.md. Each ref
   documents:
   - The runtime's preferred instructions file (CLAUDE.md, AGENTS.md,
     GEMINI.md, etc.) and how it loads
   - The runtime's personal-skills directory + cross-runtime
     ~/.agents/skills/ path where applicable
   - Action-language → tool-name mapping table

Tool names and table content reflect the source-verified state from
direct inspection of openai/codex, google-gemini/gemini-cli,
sst/opencode, and the installed @github/copilot package. Filenames
and behaviors are sourced from each runtime's official docs.

Files in this commit also pick up later-phase changes that
accumulated on the same files (using-superpowers/SKILL.md "How to
Access Skills" overhaul, action-language flowchart, refs' final
table content). The bundled spec records original scope.

skills/using-superpowers/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: using-superpowers
-description: Use when starting any conversation - establishes how to find and use skills, requiring Skill tool invocation before ANY response including clarifying questions
+description: Use when starting any conversation - establishes how to find and use skills, requiring skill invocation before ANY response including clarifying questions
 ---
 
 <SUBAGENT-STOP>
@@ -27,9 +27,13 @@ If CLAUDE.md, GEMINI.md, or AGENTS.md says "don't use TDD" and a skill says "alw
 
 ## How to Access Skills
 
-**In Claude Code:** Use the `Skill` tool. When you invoke a skill, its content is loaded and presented to you—follow it directly. Never use the Read tool on skill files.
+**Never read skill files manually with file tools** — always use your platform's skill-loading mechanism so the skill is properly activated.
 
-**In Copilot CLI:** Use the `skill` tool. Skills are auto-discovered from installed plugins. The `skill` tool works the same as Claude Code's `Skill` tool.
+**In Claude Code:** Use the `Skill` tool. When you invoke a skill, its content is loaded and presented to you — follow it directly.
+
+**In Codex:** Skills load natively. Follow the instructions presented when a skill activates.
+
+**In Copilot CLI:** Use the `skill` tool. Skills are auto-discovered from installed plugins.
 
 **In Gemini CLI:** Skills activate via the `activate_skill` tool. Gemini loads skill metadata at session start and activates the full content on demand.
 
@@ -37,7 +41,7 @@ If CLAUDE.md, GEMINI.md, or AGENTS.md says "don't use TDD" and a skill says "alw
 
 ## Platform Adaptation
 
-Skills use Claude Code tool names. Non-CC platforms: see `references/copilot-tools.md` (Copilot CLI), `references/codex-tools.md` (Codex) for tool equivalents. Gemini CLI users get the tool mapping loaded automatically via GEMINI.md.
+Skills speak in actions ("dispatch a subagent", "create a todo", "read a file") rather than naming any one runtime's tools. For per-platform tool equivalents and instructions-file conventions, see `references/claude-code-tools.md`, `references/codex-tools.md`, `references/copilot-tools.md`, and `references/gemini-tools.md`. Gemini CLI users get the tool mapping loaded automatically via GEMINI.md.
 
 # Using Skills
 
@@ -48,30 +52,30 @@ Skills use Claude Code tool names. Non-CC platforms: see `references/copilot-too
 ```dot
 digraph skill_flow {
     "User message received" [shape=doublecircle];
-    "About to EnterPlanMode?" [shape=doublecircle];
+    "About to enter plan mode?" [shape=doublecircle];
     "Already brainstormed?" [shape=diamond];
     "Invoke brainstorming skill" [shape=box];
     "Might any skill apply?" [shape=diamond];
-    "Invoke Skill tool" [shape=box];
+    "Invoke the skill" [shape=box];
     "Announce: 'Using [skill] to [purpose]'" [shape=box];
     "Has checklist?" [shape=diamond];
-    "Create TodoWrite todo per item" [shape=box];
+    "Create a todo per item" [shape=box];
     "Follow skill exactly" [shape=box];
     "Respond (including clarifications)" [shape=doublecircle];
 
-    "About to EnterPlanMode?" -> "Already brainstormed?";
+    "About to enter plan mode?" -> "Already brainstormed?";
     "Already brainstormed?" -> "Invoke brainstorming skill" [label="no"];
     "Already brainstormed?" -> "Might any skill apply?" [label="yes"];
     "Invoke brainstorming skill" -> "Might any skill apply?";
 
     "User message received" -> "Might any skill apply?";
-    "Might any skill apply?" -> "Invoke Skill tool" [label="yes, even 1%"];
+    "Might any skill apply?" -> "Invoke the skill" [label="yes, even 1%"];
     "Might any skill apply?" -> "Respond (including clarifications)" [label="definitely not"];
-    "Invoke Skill tool" -> "Announce: 'Using [skill] to [purpose]'";
+    "Invoke the skill" -> "Announce: 'Using [skill] to [purpose]'";
     "Announce: 'Using [skill] to [purpose]'" -> "Has checklist?";
-    "Has checklist?" -> "Create TodoWrite todo per item" [label="yes"];
+    "Has checklist?" -> "Create a todo per item" [label="yes"];
     "Has checklist?" -> "Follow skill exactly" [label="no"];
-    "Create TodoWrite todo per item" -> "Follow skill exactly";
+    "Create a todo per item" -> "Follow skill exactly";
 }
 ```