fix: abort signal in polling loops, remove legacy k2p5, pass ctx.directory to skill tool

- Check context.abort in background-wait and background-output polling loops
- Remove legacy kimi-for-coding/k2p5 from athena fallback chain
- Pass ctx.directory from tool-registry to createSkillTool instead of process.cwd()

src/shared/model-requirements.ts

@@ -183,7 +183,6 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   athena: {
     fallbackChain: [
       { providers: ["anthropic", "github-copilot", "opencode"], model: "claude-opus-4-6", variant: "max" },
-      { providers: ["kimi-for-coding"], model: "k2p5" },
       { providers: ["opencode"], model: "kimi-k2.5-free" },
       { providers: ["zai-coding-plan"], model: "glm-4.7" },
       { providers: ["opencode"], model: "glm-4.7-free" },