feat(v0.6.1): file_reread signal — catch offset-shifted same-file re-reads

Proposed and approved through ADAM's own /reflect harness_edit loop (MOSS §1):
the analyst surfaced 23 tool_error_loop entries across 4 sessions whose context
windows were really redundant re-reads of one file.

retry_loop keys on argsHash of the full tool_input (including offset/limit), so
consecutive Reads of the SAME file at different offsets escaped dedup and leaked
into tool_error_loop fingerprints. The new file_reread signal catches them:
same file Read >=3x in the 10-event window, offset-agnostic (keyed on file
path), guarded by `sameToolArgs < RETRY_THRESHOLD` so byte-identical reads stay
with retry_loop (no double-count).

Fully wired end-to-end (not a half-dead signal):
- adam-observe.mjs: detection + STRUGGLE_TYPES membership (so it carries
  context_window + active_skills like other struggle signals).
- adam-window.mjs: 14-day sliding window (task-local, like retry_loop).
- adam-score.mjs: severity divisor 3.
- adam-batch.mjs: file-basename clustering.
- agents/adam.md + README: signal tables, clustering rules, rubric, windows.

Tests: 126 -> 132 (file_reread fires on 3x offset-shifted reads, not on 2x;
byte-identical reads route to retry_loop not file_reread; carries context_window).

adam/scripts/adam-window.mjs

@@ -30,6 +30,7 @@ export const SIGNAL_WINDOWS_DAYS = {
   weak_agent: 30,
   subagent_dispatch_pattern: 30,
   silent_drift: 14,
+  file_reread: 14,
   error_after_recovery: 30,
   correction_free_streak: 60,
   clean_recovery: 60,