feat(run): configurable token budget limit

[LarsCowe]

Problem

No way to cap total token spend for a Ralph session. MAX_CALLS_PER_HOUR limits API calls per hour but not cumulative cost.

Proposal

New config option MAX_TOTAL_TOKENS=0 in .ralphrc (0 = unlimited):

1. Track cumulative tokens across all loop iterations
2. When cumulative tokens exceed the budget, gracefully exit (same flow as rate limit)
3. Display remaining budget in the dashboard

Depends on #127 (token tracking).

Files

• ralph/ralph_loop.sh — can_make_call() (line 769)
• ralph/templates/ralphrc.template

Priority

14/16 — Medium impact, 2 hours effort