fix(workspace): make cross-repo co-change a bounded session-share signal (#758)

* fix(workspace): make cross-repo co-change a bounded session-share signal

The cross-repo co-change list was dominated by noise: a progress diary
paired with everything (103 of 200 edges), strengths were unbounded sums
(up to 91.6 against an API contract of 0..1), one repo pair consumed the
whole edge budget, and same-person commits under different git emails
never matched at all.

Reworked detect_cross_repo_co_changes:
- Chain each author's commits into work sessions (gap or span > window
  starts a new one). A session credits each cross-repo file pair once,
  killing the quadratic commit-pair inflation that let one diary file
  reach frequency 322 from 38 commits.
- Match authors by normalized author name with email fallback, so the
  same person committing as 'Jane Doe' and 'JaneDoe' with different
  emails still links their repos.
- Drop ubiquitous files (>20% of a repo's scanned commits, only when
  >=30 commits of history) plus changelogs via the static noise list.
- strength = decayed co-sessions / (less-active file's decayed sessions
  + 1), a bounded [0, 1) share; require >=2 co-sessions. frequency now
  means distinct co-sessions.
- Cap sessions at 20 files per side selected by session centrality, not
  alphabetically (which systematically evicted src/** in busy sessions),
  and cap edges per repo pair (50) before the global cap (200).

Overlay version bumped to 2; load_overlay and CrossRepoEnricher ignore
v1 files so stale unbounded scores never reach consumers. The CLAUDE.md
workspace generator now reads through load_overlay instead of parsing
the JSON three times. UI shows strength as a percentage with an updated
tooltip, and the min_strength API bound (le=1.0) is now truthful.

Dogfood validation across repowise+backend+frontend: 0 diary edges (was
116/200), strengths 0.52-0.78, all three repo pairs represented (was 1).

* fix(upgrade): sync bundled changelog with docs

Author: RaghavChamadiya

packages/cli/src/repowise/cli/commands/claude_md_cmd.py

@@ -203,8 +203,8 @@ def _generate_workspace(
         WORKSPACE_DATA_DIR,
         WorkspaceConfig,
     )
-    from repowise.core.workspace.cross_repo import CROSS_REPO_EDGES_FILENAME
     from repowise.core.workspace.contracts import CONTRACTS_FILENAME
+    from repowise.core.workspace.cross_repo import load_overlay
 
     ws_root = find_workspace_root(start_path)
     if ws_root is None:
@@ -220,14 +220,14 @@ def _generate_workspace(
     # ------------------------------------------------------------------
     co_changes: list[dict] = []
     package_deps: list[dict] = []
-    edges_file = data_dir / CROSS_REPO_EDGES_FILENAME
-    if edges_file.exists():
-        try:
-            overlay = json.loads(edges_file.read_text(encoding="utf-8"))
-            co_changes = overlay.get("co_changes", [])
-            package_deps = overlay.get("package_deps", [])
-        except Exception:
-            pass  # non-fatal; workspace data may not exist yet
+    overlay_summaries: dict[str, dict] = {}
+    overlay = load_overlay(ws_root)  # None when absent, corrupt, or stale-versioned
+    if overlay is not None:
+        from dataclasses import asdict
+
+        co_changes = [asdict(c) for c in overlay.co_changes]
+        package_deps = [asdict(d) for d in overlay.package_deps]
+        overlay_summaries = overlay.repo_summaries
 
     # Sort co-changes by frequency descending so the top entries are most useful
     co_changes = sorted(co_changes, key=lambda c: c.get("frequency", 0), reverse=True)
@@ -257,25 +257,9 @@ def _generate_workspace(
         abs_path = (ws_root / entry.path).resolve()
         file_count, symbol_count = _query_repo_counts(abs_path)
 
-        # Hotspot count: try to read from the overlay's repo_summaries if available
-        hotspot_count = 0
-        if edges_file.exists():
-            try:
-                overlay_data = json.loads(edges_file.read_text(encoding="utf-8"))
-                repo_sum = overlay_data.get("repo_summaries", {}).get(entry.alias, {})
-                hotspot_count = repo_sum.get("hotspot_count", 0)
-            except Exception:
-                pass
-
-        # Entry points: read from overlay repo_summaries if present, else empty
-        entry_points: list[str] = []
-        if edges_file.exists():
-            try:
-                overlay_data = json.loads(edges_file.read_text(encoding="utf-8"))
-                repo_sum = overlay_data.get("repo_summaries", {}).get(entry.alias, {})
-                entry_points = repo_sum.get("entry_points", [])
-            except Exception:
-                pass
+        repo_sum = overlay_summaries.get(entry.alias, {})
+        hotspot_count = repo_sum.get("hotspot_count", 0)
+        entry_points = repo_sum.get("entry_points", [])
 
         repo_summaries.append(
             WorkspaceRepoSummary(