feat: unify mosaic CLI — single binary, no PATH conflict

- Rename framework bash launcher: mosaic → mosaic-launch
- npm CLI (@mosaic/cli) is now the single 'mosaic' binary on PATH
- Add launcher delegation: mosaic {claude,codex,opencode,pi,yolo}
  delegates to mosaic-launch via execFileSync with inherited stdio
- Add delegated management commands: init, doctor, sync, seq,
  bootstrap, coord, upgrade
- install.sh: remove framework bin PATH requirement, clean up old
  mosaic binary on upgrade, simplified summary output
- framework install.sh: preserve sources/ dir (fixes rsync noise
  about agent-skills)
- session-run.sh: update references to mosaic-launch

Users now only need ~/.npm-global/bin on PATH. The npm CLI finds
mosaic-launch at its absolute path (~/.config/mosaic/bin/mosaic-launch).

tools/install.sh

@@ -202,13 +202,8 @@ if [[ "$FLAG_FRAMEWORK" == "true" ]]; then
     ok "Framework installed"
     echo ""
 
-    # Ensure framework bin is on PATH
-    FRAMEWORK_BIN="$MOSAIC_HOME/bin"
-    if [[ ":$PATH:" != *":$FRAMEWORK_BIN:"* ]]; then
-      warn "$FRAMEWORK_BIN is not on your PATH"
-      dim "  The 'mosaic' launcher lives here. Add to your shell rc:"
-      dim "  export PATH=\"$FRAMEWORK_BIN:\$PATH\""
-    fi
+    # Framework bin is no longer needed on PATH — the npm CLI delegates
+    # to mosaic-launch directly via its absolute path.
   fi
 fi
 
@@ -290,7 +285,6 @@ if [[ "$FLAG_CLI" == "true" ]]; then
     # PATH check for npm prefix
     if [[ ":$PATH:" != *":$PREFIX/bin:"* ]]; then
       warn "$PREFIX/bin is not on your PATH"
-      dim "  The 'mosaic' TUI/gateway CLI lives here (separate from the launcher)."
       dim "  Add to your shell rc:  export PATH=\"$PREFIX/bin:\$PATH\""
     fi
   fi
@@ -303,26 +297,19 @@ fi
 if [[ "$FLAG_CHECK" == "false" ]]; then
   step "Summary"
 
-  echo "  ${BOLD}Framework launcher:${RESET}  $MOSAIC_HOME/bin/mosaic"
-  echo "    ${DIM}mosaic claude, mosaic yolo claude, mosaic pi, mosaic doctor, …${RESET}"
-  echo ""
-  echo "  ${BOLD}npm CLI (TUI):${RESET}       $PREFIX/bin/mosaic"
-  echo "    ${DIM}mosaic tui, mosaic login, mosaic wizard, mosaic update, …${RESET}"
+  echo "  ${BOLD}mosaic CLI:${RESET}  $PREFIX/bin/mosaic"
+  dim "    All commands: mosaic claude, mosaic yolo pi, mosaic tui, mosaic doctor, …"
   echo ""
+  dim "  Framework data:  $MOSAIC_HOME/"
+  dim "  Launcher backend: $MOSAIC_HOME/bin/mosaic-launch"
 
-  # Warn if there's a naming collision (both on PATH)
+  # Clean up old mosaic binary from PATH if framework bin is still there
   FRAMEWORK_BIN="$MOSAIC_HOME/bin"
-  if [[ ":$PATH:" == *":$FRAMEWORK_BIN:"* ]] && [[ ":$PATH:" == *":$PREFIX/bin:"* ]]; then
-    # Check which one wins
-    WHICH_MOSAIC="$(command -v mosaic 2>/dev/null || true)"
-    if [[ -n "$WHICH_MOSAIC" ]]; then
-      dim "  Active 'mosaic' binary: $WHICH_MOSAIC"
-      if [[ "$WHICH_MOSAIC" == "$FRAMEWORK_BIN/mosaic" ]]; then
-        dim "  (Framework launcher takes priority — this is correct)"
-      else
-        warn "npm CLI shadows the framework launcher!"
-        dim "  Ensure $FRAMEWORK_BIN appears BEFORE $PREFIX/bin in your PATH."
-      fi
+  if [[ ":$PATH:" == *":$FRAMEWORK_BIN:"* ]]; then
+    OLD_MOSAIC="$FRAMEWORK_BIN/mosaic"
+    if [[ -f "$OLD_MOSAIC" ]] && [[ ! -L "$OLD_MOSAIC" ]]; then
+      info "Removing old framework 'mosaic' binary (replaced by npm CLI)"
+      rm -f "$OLD_MOSAIC"
     fi
   fi