feat: add API explorer and agent tool interface

[atomantic]

Summary

• Add a discoverable Dev Tools → API Explorer with Catalog, REST/OpenAPI, Event/AsyncAPI, and Agent Tools views.
• Generate deterministic contracts for 2,066 HTTP operations and 253 Socket.IO events, with drift tests and source evidence.
• Reuse one capability-oriented semantic tool registry across Persistent Mind, agent-context MCP, HTTP, and voice adapters.
• Keep agent grants default-off and execution bounded with shared task budgets, cancellation propagation, normalized failures, and retained idempotency fingerprints.
• Add registry-backed API access settings, hosted Scalar reference rendering, and operator/developer documentation.

Review

• Completed a batched local review across client UX, generated contracts, and server/tool execution.
• Addressed catalog load/error state, registry settings-key parity, toggle accessibility, composed router and distributed Socket.IO discovery, AsyncAPI path parameters, task/tool budget sharing, cancellation, idempotency retention, and explicit rejected-action outcomes.

Test plan

• cd client && node node_modules/vitest/vitest.mjs run — 796 files / 10,079 tests passed.
• Focused post-rebase client suites — 5 files / 103 tests passed.
• Focused post-rebase server and contract suites — 11 files / 71 tests passed.
• Full server suite completed with no feature failures; the only failure is the existing scripts/trusted-rebuilds.test.js environment check because this linked worktree does not contain the optional node-pty install-hook package.
• npm run generate:api-docs — deterministic output: 2,066 HTTP operations and 253 Socket.IO events.
• cd client && node node_modules/vite/bin/vite.js build — production build passed (9,974 modules).