Ship the batch: undo, parallel subagents, lazy MCP, hot-reloaded skills; docs and CI/CD

Loop and ergonomics batch across Now/Next and Maintenance:
- /undo and /redo via pre-prompt file snapshots (snapshot.ts)
- task takes a tasks[] array and runs investigations concurrently (subagent.ts)
- lazy MCP tools: mcp_list/mcp_inspect/mcp_call meta-tools, eager opt-in (mcp.ts, config.ts)
- skill tool reads its list live so a mid-session install is callable next turn (skills.ts)
- tool-name lists (tool-kinds.ts) derived from a mutating() marker; gates previously ungated writes
- prune/session recovery path summarized, and step-back doom-loop primitive (step-back.ts)
- @file completion re-walks on a slow cooldown; estimateTokens and pricing labeled as estimates

Docs: README, CHANGELOG, docs/{mcp,architecture,development} updated to match.
CI/CD: bun install-store cache and concurrency gates on both workflows; release.yml now
composes file-based release notes via scripts/make-release-notes.ts and verifies every binary.

src/config.ts

@@ -37,6 +37,11 @@ export type Config = {
   /** Index for `/registry`. Omit for the default one. */
   registryUrl?: string;
   mcpServers?: Record<string, McpServerConfig>;
+  /**
+   * How MCP tools reach the model: `lazy` registers meta-tools only (cheap until a
+   * tool is called), `eager` registers every server tool up front. Omit for lazy.
+   */
+  mcpMode?: 'lazy' | 'eager';
 };
 
 const configPath = () => join(process.env['SHIRO_HOME'] ?? homedir(), '.shiro-neko', 'config.json');