feat: General Agent SDK source-sync — full runtime alignment with OpenClaw embedded seam

[Redux0223]

Summary

Complete implementation of the General Agent SDK source-sync design spec, converting the SDK from a simplified prototype into a production-ready embedded agent runtime aligned with OpenClaw's embedded seam.

Key Changes

Runtime & Core

• Fix multi-turn conversation memory — agentMessages now correctly accumulate across turns via agent_end event handling
• Fix API key env var fallback — process.env.ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL are now correctly resolved
• Implement working compaction runtime with truncation strategy + lifecycle hooks
• Replace hardcoded 200K context window with dynamic model-based resolution
• Add transcript repair/validation for robust message ordering
• Implement restart-safe hosted-tool continuation (single + multi-tool suspensions)
• Implement first-class subagent runtime with independent child sessions, scoped tools, lifecycle hooks
• Wire steering messages and follow-up messages into the agent loop
• Missing credentials now fail loudly (throw Error) — no silent stub completions

Public API Surface

• Remove all VisionClaw compatibility code and exports (src/compat/visionclaw/*)
• Standardize all naming on GeneralAgent* prefix
• Add session lifecycle: listSessions, resumeSession, forkSession, reset, readSessionHistory
• Add file checkpointing and rollback API
• Add dynamic MCP server management (stdio + http transports)
• Expose full 26-hook system (19 SDK-native auto-fired + 7 host-bridged)

Tools

• Source-sync web_search with Brave/DuckDuckGo dual provider runtime
• Source-sync web_fetch with readability, Firecrawl integration, SSRF protection
• Add subagents as core built-in tool (independent child sessions, not host-bridged)
• Add apply_patch tool with unified diff support
• Classify all OpenClaw tools: core-built-in / optional / host-bridged / out-of-scope

Documentation (SDK DOCS/)

• 8 runnable TypeScript examples covering all core features
• Complete API reference document
• Updated README with architecture, events, tools, hooks, and integration guide

Acceptance Criteria (15/15 ✅)

All 15 acceptance criteria from the design spec are fully satisfied:

1. ✅ Autonomous multi-turn tool/model execution
2. ✅ Source-synced web_search and web_fetch
3. ✅ Complete tool classification
4. ✅ Hosted tools suspend/resume same run (restart-safe)
5. ✅ Structured tool result details
6. ✅ Session create/continue/resume/fork/list/history/reset
7. ✅ 26-hook system (19 SDK-native + 7 host-bridged)
8. ✅ Host-bridged hooks via sdk.emitHook()
9. ✅ MCP stdio + http transports
10. ✅ First-class subagent runtime with lifecycle hooks
11. ✅ Streaming with incremental events + terminal completion
12. ✅ File checkpointing and rewind
13. ✅ Missing credentials hard-fail
14. ✅ VisionClaw code fully removed
15. ✅ GeneralAgent* naming standardized

Test Plan

• pnpm run check — TypeScript compilation passes
• pnpm run build — Production build succeeds
• pnpm run test — 133 unit/integration tests pass
• pnpm run test:e2e — Package smoke test passes
• node scripts/verify-upstream-snapshot.mjs — Provenance verified
• Real API E2E tests (5/5 pass): basic chat, multi-turn memory, hosted tools, built-in file tools, session lifecycle

Files Changed

• 106 files changed, 21065 insertions, 1104 deletions
• New: 66 files (core runtime, tools, hooks, MCP, tests, docs)
• Modified: 34 files (session, loop, events, types, tests)
• Deleted: 6 files (VisionClaw compat layer)