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-batch.mjs

@@ -11,6 +11,7 @@
 //   tool_error_loop→ fp
 //   dead_end       → session
 //   edit_churn     → file basename
+//   file_reread    → file basename
 //   build_loop     → session
 //   subagent_dispatch_pattern → subagent_type
 //   silent_drift   → active_skills[0]
@@ -65,6 +66,7 @@ function clusterKey(entry) {
     case "build_loop":
       return entry.session || "unknown";
     case "edit_churn":
+    case "file_reread":
       return entry.file ? entry.file.split("/").pop() : "unknown";
     case "silent_drift":
     case "correction_free_streak":