Update README.MD and add nano-claude-code v3.0 + original-source-code/src

- README.MD: add original-source-code and nano-claude-code sections, update
  overview table (4 subprojects), add v3.0 news entry, expand comparison table
  with memory/multi-agent/skills dimensions
- nano-claude-code v3.0: multi-agent package (multi_agent/), memory package
  (memory/), skill package (skill/) with built-in /commit and /review skills,
  context compression (compaction.py), tool registry plugin system, diff view,
  17 slash commands, 18 built-in tools, 101 tests (~5000 lines total)
- original-source-code/src: add raw TypeScript source tree (1884 files)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nano-claude-code/agent.py

@@ -5,8 +5,11 @@ import uuid
 from dataclasses import dataclass, field
 from typing import Generator
 
-from tools import TOOL_SCHEMAS, execute_tool
+from tool_registry import get_tool_schemas
+from tools import execute_tool
+import tools as _tools_init  # ensure built-in tools are registered on import
 from providers import stream, AssistantTurn, TextChunk, ThinkingChunk, detect_provider
+from compaction import maybe_compact
 
 # ── Re-export event types (used by nano_claude.py) ────────────────────────
 __all__ = [
@@ -54,25 +57,39 @@ def run(
     state: AgentState,
     config: dict,
     system_prompt: str,
+    depth: int = 0,
+    cancel_check=None,
 ) -> Generator:
     """
     Multi-turn agent loop (generator).
     Yields: TextChunk | ThinkingChunk | ToolStart | ToolEnd |
             PermissionRequest | TurnDone
+
+    Args:
+        depth: sub-agent nesting depth, 0 for top-level
+        cancel_check: callable returning True to abort the loop early
     """
     # Append user turn in neutral format
     state.messages.append({"role": "user", "content": user_message})
 
+    # Inject runtime metadata into config so tools (e.g. Agent) can access it
+    config = {**config, "_depth": depth, "_system_prompt": system_prompt}
+
     while True:
+        if cancel_check and cancel_check():
+            return
         state.turn_count += 1
         assistant_turn: AssistantTurn | None = None
 
+        # Compact context if approaching window limit
+        maybe_compact(state, config)
+
         # Stream from provider (auto-detected from model name)
         for event in stream(
             model=config["model"],
             system=system_prompt,
             messages=state.messages,
-            tool_schemas=TOOL_SCHEMAS,
+            tool_schemas=get_tool_schemas(),
             config=config,
         ):
             if isinstance(event, (TextChunk, ThinkingChunk)):
@@ -114,6 +131,7 @@ def run(
                 result = execute_tool(
                     tc["name"], tc["input"],
                     permission_mode="accept-all",  # already gate-checked above
+                    config=config,
                 )
 
             yield ToolEnd(tc["name"], result, permitted)