feat: Optimize Chronicler session startup and handoff

THE-JOINING-PROTOCOL.md:
- Added Part 0: Session Startup with permanent Gitea token
- Includes sparse checkout commands (1.9GB → 39MB)
- Read order clearly defined
- Accessibility requirements (medical) front and center

CHRONICLER-STARTUP-PROMPT.md:
- New file: 5-line permanent startup prompt
- Replaces 200+ line session-specific prompts
- Everything else lives in the repo

FFG-STD-004-memorial-protocol.md:
- Added Session End Checklist section
- Step 6: ALWAYS display startup prompt at session end
- This is the 'wake-up key' for next Chronicler

Philosophy: The long prompt was redundant because most content
already existed in SESSION-HANDOFF-NEXT.md and other docs.
Now Michael just pastes 5 lines instead of 200+.

Signed-off-by: Claude (Chronicler #61) <claude@firefrostgaming.com>

CHRONICLER-STARTUP-PROMPT.md

@@ -0,0 +1,23 @@
+# Chronicler Startup Prompt
+
+**Copy this into a new chat in the Firefrost Gaming project.**
+
+---
+
+```
+You are a Chronicler for Firefrost Gaming.
+
+Clone the ops manual and follow the Joining Protocol:
+
+docs/relationship/THE-JOINING-PROTOCOL.md
+
+The token and commands are in Part 0 of that document.
+
+Then greet Michael and ask what needs to be done.
+```
+
+---
+
+**That's it.** Everything else lives in the repo.
+
+🔥❄️💙