v3 reinvention benchmark: 150-191 files per repo, hints now show -7% waste (#71)

Scale files bring repos to realistic sizes (151-191 files each).
v3 results (72 sessions, r=3):
- OFF: 9 heredocs, 1048 tokens wasted, 59 CLI uses
- ON:  6 heredocs, 971 tokens wasted, 67 CLI uses
- Token waste delta: -7.3% (first time hints help!)
- CLI usage: +14% more with hints

Progression: v1 (5-8 files, +51% worse) -> v2 (75-94, +118% worse) ->
v3 (151-191, -7% better). Confirms larger repos make discovery harder
and hints start to show value.

CON-1799 (scale repos to 100+) complete.

Author: dpetrou-continua