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/memory/scan.py

@@ -0,0 +1,144 @@
+"""Memory file scanning with mtime tracking and freshness/age helpers.
+
+Mirrors the key ideas from Claude Code's memoryScan.ts and memoryAge.ts:
+  - Scan memory directories, sort newest-first
+  - Format a manifest for display or AI relevance selection
+  - Report memory age in human-readable form ("today", "3 days ago")
+  - Emit a staleness caveat for memories older than 1 day
+"""
+from __future__ import annotations
+
+import math
+import time
+from dataclasses import dataclass
+from pathlib import Path
+
+from .store import get_memory_dir, parse_frontmatter, INDEX_FILENAME
+
+MAX_MEMORY_FILES = 200
+
+
+# ── Data model ─────────────────────────────────────────────────────────────
+
+@dataclass
+class MemoryHeader:
+    """Lightweight descriptor loaded from a memory file's frontmatter.
+
+    Attributes:
+        filename:    basename of the .md file
+        file_path:   absolute path
+        mtime_s:     modification time (seconds since epoch)
+        description: value from frontmatter `description:` field
+        type:        value from frontmatter `type:` field
+        scope:       "user" or "project"
+    """
+    filename: str
+    file_path: str
+    mtime_s: float
+    description: str
+    type: str
+    scope: str
+
+
+# ── Scanning ───────────────────────────────────────────────────────────────
+
+def scan_memory_dir(mem_dir: Path, scope: str) -> list[MemoryHeader]:
+    """Scan a single memory directory and return headers sorted newest-first.
+
+    Reads only the frontmatter (first ~30 lines) for efficiency.
+    Silently skips unreadable files. Caps at MAX_MEMORY_FILES entries.
+    """
+    if not mem_dir.is_dir():
+        return []
+
+    headers: list[MemoryHeader] = []
+    for fp in mem_dir.glob("*.md"):
+        if fp.name == INDEX_FILENAME:
+            continue
+        try:
+            stat = fp.stat()
+            # Read only the first 30 lines for frontmatter
+            lines = fp.read_text(errors="replace").splitlines()[:30]
+            snippet = "\n".join(lines)
+            meta, _ = parse_frontmatter(snippet)
+            headers.append(MemoryHeader(
+                filename=fp.name,
+                file_path=str(fp),
+                mtime_s=stat.st_mtime,
+                description=meta.get("description", ""),
+                type=meta.get("type", ""),
+                scope=scope,
+            ))
+        except Exception:
+            continue
+
+    headers.sort(key=lambda h: h.mtime_s, reverse=True)
+    return headers[:MAX_MEMORY_FILES]
+
+
+def scan_all_memories() -> list[MemoryHeader]:
+    """Scan both user and project memory directories, merged newest-first."""
+    user_dir = get_memory_dir("user")
+    proj_dir = get_memory_dir("project")
+
+    user_headers = scan_memory_dir(user_dir, "user")
+    proj_headers = scan_memory_dir(proj_dir, "project")
+
+    combined = user_headers + proj_headers
+    combined.sort(key=lambda h: h.mtime_s, reverse=True)
+    return combined[:MAX_MEMORY_FILES]
+
+
+# ── Age / freshness ────────────────────────────────────────────────────────
+
+def memory_age_days(mtime_s: float) -> int:
+    """Days since mtime_s (floor-rounded, clamped to 0 for future times)."""
+    return max(0, math.floor((time.time() - mtime_s) / 86_400))
+
+
+def memory_age_str(mtime_s: float) -> str:
+    """Human-readable age: 'today', 'yesterday', or 'N days ago'."""
+    d = memory_age_days(mtime_s)
+    if d == 0:
+        return "today"
+    if d == 1:
+        return "yesterday"
+    return f"{d} days ago"
+
+
+def memory_freshness_text(mtime_s: float) -> str:
+    """Staleness caveat for memories older than 1 day (empty string if fresh).
+
+    Motivated by user reports of stale code-state memories (file:line
+    citations to code that has since changed) being asserted as fact.
+    """
+    d = memory_age_days(mtime_s)
+    if d <= 1:
+        return ""
+    return (
+        f"This memory is {d} days old. "
+        "Memories are point-in-time observations, not live state — "
+        "claims about code behavior or file:line citations may be outdated. "
+        "Verify against current code before asserting as fact."
+    )
+
+
+# ── Manifest formatting ────────────────────────────────────────────────────
+
+def format_memory_manifest(headers: list[MemoryHeader]) -> str:
+    """Format a list of MemoryHeader as a text manifest.
+
+    Format per line:  [type/scope] filename (age): description
+    Example:
+        [feedback/user] feedback_testing.md (3 days ago): Don't mock DB in tests
+        [project/project] project_freeze.md (today): Merge freeze until 2026-04-10
+    """
+    lines = []
+    for h in headers:
+        tag = f"[{h.type}/{h.scope}]" if h.type else f"[{h.scope}]"
+        age = memory_age_str(h.mtime_s)
+        if h.description:
+            lines.append(f"- {tag} {h.filename} ({age}): {h.description}")
+        else:
+            lines.append(f"- {tag} {h.filename} ({age})")
+    return "\n".join(lines)