feat(memory): FPLAN-0276 — unify memory limits into config single-source + cleanup

- memory.config.json is the single source of truth: char caps (entry_limits, global) + rollover counts (per_branch, materialized from registry); .trinity files stripped to a one-line _usage header
- changed_entries gate now matches by content identity, not array position — prepending a new entry never re-flags unchanged legacy entries (old=old, new=new; no trimming required on a cap change)
- rollover push command + top-level 'drone @memory push' alias; corrected config _note + --help (rollover push surfaced, labeled destructive system-wide reset)
- removed 3 dead functions: seed_per_branch, its orphaned write_config, add_learning + its tests
- spawn birthright/builder + LOCAL/OBSERVATIONS templates aligned to the stripped shape
- 966 tests, seedgo 100%

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/aipass/spawn/templates/birthright/.trinity/local.json

@@ -12,20 +12,14 @@
       "work_log",
       "{{BRANCHNAME}}"
     ],
-    "limits": {
-      "max_sessions": 20,
-      "max_key_learnings": 25,
-      "session_summary_max_chars": 150,
-      "learning_value_max_chars": 200,
-      "note": "DO NOT trim, prune, or delete entries. Rollover to @memory handles overflow automatically. Just add new entries."
-    },
+    "_usage": "Automated file — add entries within your sections; rollover trims automatically. Limits live in @memory's memory.config.json.",
     "status": {
       "health": "healthy",
-      "last_health_check": "{{DATE}}",
-      "current_lines": 0
+      "last_health_check": "{{DATE}}"
     }
   },
   "key_learnings": [],
+  "todos": [],
   "sessions": [
     {
       "number": 1,

src/aipass/spawn/templates/birthright/.trinity/observations.json

@@ -12,13 +12,9 @@
       "patterns",
       "{{BRANCHNAME}}"
     ],
-    "limits": {
-      "max_lines": 600,
-      "note": "DO NOT trim, prune, or delete entries. Auto-rollover to @memory when max_lines exceeded."
-    },
+    "_usage": "Automated file — add entries within your sections; rollover trims automatically. Limits live in @memory's memory.config.json.",
     "status": {
       "health": "healthy",
-      "current_lines": 0,
       "last_health_check": "{{DATE}}"
     }
   },

src/aipass/spawn/templates/builder/.trinity/local.json

@@ -12,23 +12,14 @@
       "work_log",
       "{{BRANCHNAME}}"
     ],
-    "limits": {
-      "max_sessions": 20,
-      "max_key_learnings": 25,
-      "session_summary_max_chars": 150,
-      "learning_value_max_chars": 200,
-      "note": "DO NOT trim, prune, or delete entries. Rollover to @memory handles overflow automatically. Just add new entries. todos[] is OPERATIONAL — never vectorized/trimmed by rollover; completing/removing a todo is normal.",
-      "max_todos": 10,
-      "todo_text_max_chars": 200
-    },
+    "_usage": "Automated file — add entries within your sections; rollover trims automatically. Limits live in @memory's memory.config.json.",
     "status": {
       "health": "healthy",
-      "last_health_check": "{{DATE}}",
-      "current_lines": 0
+      "last_health_check": "{{DATE}}"
     }
   },
-  "todos": [],
   "key_learnings": [],
+  "todos": [],
   "sessions": [
     {
       "number": 1,
@@ -38,4 +29,4 @@
       "tags": []
     }
   ]
-}
+}

src/aipass/spawn/templates/builder/.trinity/observations.json

@@ -12,13 +12,9 @@
       "patterns",
       "{{BRANCHNAME}}"
     ],
-    "limits": {
-      "max_lines": 600,
-      "note": "DO NOT trim, prune, or delete entries. Auto-rollover to @memory when max_lines exceeded."
-    },
+    "_usage": "Automated file — add entries within your sections; rollover trims automatically. Limits live in @memory's memory.config.json.",
     "status": {
       "health": "healthy",
-      "current_lines": 0,
       "last_health_check": "{{DATE}}"
     }
   },