feat: Vestige v1.9.1 AUTONOMIC — self-regulating memory with graph visualization

Retention Target System: auto-GC low-retention memories during consolidation
(VESTIGE_RETENTION_TARGET env var, default 0.8). Auto-Promote: memories
accessed 3+ times in 24h get frequency-dependent potentiation. Waking SWR
Tagging: promoted memories get preferential 70/30 dream replay. Improved
Consolidation Scheduler: triggers on 6h staleness or 2h active use.

New tools: memory_health (retention dashboard with distribution buckets,
trend tracking, recommendations) and memory_graph (subgraph export with
Fruchterman-Reingold force-directed layout, up to 200 nodes).

Dream connections now persist to database via save_connection(), enabling
memory_graph traversal. Schema Migration V8 adds waking_tag, utility_score,
times_retrieved/useful columns and retention_snapshots table. 21 MCP tools.

v1.9.1 fixes: ConnectionRecord export, UTF-8 safe truncation, link_type
normalization, utility_score clamping, only-new-connections persistence,
70/30 split capacity fill, nonexistent center_id error handling.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.lock

@@ -3655,7 +3655,7 @@ checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
 [[package]]
 name = "vestige-core"
-version = "1.7.0"
+version = "1.9.1"
 dependencies = [
  "chrono",
  "directories",
@@ -3689,7 +3689,7 @@ dependencies = [
 
 [[package]]
 name = "vestige-mcp"
-version = "1.7.0"
+version = "1.9.1"
 dependencies = [
  "anyhow",
  "axum",