Added README user guide, new shots start at frame 1001

README.md documents installation, the Sanity Check, Rename and Shot
Viewer tools, the config overrides and troubleshooting.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

config.py

@@ -247,7 +247,7 @@ SHOT_VIEWER_RIG_GROUPS = {
 # Shots added by the shot viewer. TODO: confirm with production.
 SHOT_NAME_FORMAT = "sh{:04d}"
 SHOT_NUMBER_STEP = 10
-SHOT_FRAME_START = 101
+SHOT_FRAME_START = 1001
 SHOT_DEFAULT_DURATION = 48
 
 # --------------------------------------------------------------------------- #