fix: disambiguate project profiles that share a directory basename (#74)

discover_project_configs labelled every project by basename alone, so
~/work/app/.mcp.json and ~/personal/app/.mcp.json both read as
"Project: app". Paths dedupe correctly, so both profiles existed -- they
were just indistinguishable in the picker, and picking the wrong one meant
editing, backing up, and writing the wrong repo's config. api/web/app/
server/client as repo names make this common.

- disambiguate_project_labels(dirs): pure, testable. Labels stay
  "Project: <name>" until a basename collides, then only the colliding
  ones widen toward the root one component at a time
  ("Project: work/app" vs "Project: personal/app"), widening further if the
  parent also collides. The common no-collision case is unchanged.
- Full path goes in the combo item's ToolTipRole, so a profile is always
  verifiable by hover regardless of label.
- Tightened the "is this a project config?" check: the docstring claimed a
  top-level object but the code only checked is_file(), so a .mcp.json that
  was a JSON array or garbage still became a profile and only failed on
  open. It now must parse (strict) to a dict, else it's skipped.

Tests: +6 (no-collision basename, colliding widen, deeper widen, and
discover_project_configs disambiguation + skipping array/garbage/missing).
463 passed, ruff clean.

Closes #74

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EKwBecy6N83jnqQmw8ezwE

bcc.py

@@ -2043,6 +2043,11 @@ class MainWindow(QMainWindow):
         for p in self.profiles:
             tag = "" if p.config_exists else "  (no config yet)"
             self.profile_combo.addItem(f"{p.label}{tag}")
+            # Full path in the tooltip so a profile is always verifiable even
+            # when two labels look alike (e.g. two repos both named "app").
+            self.profile_combo.setItemData(
+                self.profile_combo.count() - 1, str(p.path), Qt.ItemDataRole.ToolTipRole
+            )
         self.profile_combo.blockSignals(False)
         if self.profiles:
             self.profile_combo.setCurrentIndex(0)