docs: remove stale libSQL/async references and dead reference docs

- CLAUDE.md: update to 2 crates, json_store description
- Delete performance-checklist.md, testing-patterns.md,
  security-checklist.md (described old async/libSQL architecture)
- Fix token-optimization-audit.md flowctl-db refs → flowctl-core
- Fix adr-guide.md example ADR name

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: z23cc

CLAUDE.md

@@ -13,7 +13,7 @@ commands/flow-code/*.md  → Slash command definitions (user-invocable entry poi
 skills/*/SKILL.md        → Skill implementations (loaded by Skill tool, never Read directly)
 agents/*.md              → Subagent definitions (research scouts, worker, plan-sync, etc.)
 bin/flowctl               → Rust binary (built from flowctl/ workspace)
-flowctl/                  → Rust Cargo workspace (4 crates: core, db, service, cli)
+flowctl/                  → Rust Cargo workspace (2 crates: core, cli)
 hooks/hooks.json         → Ralph workflow guards (active when FLOW_RALPH=1)
 docs/                    → Architecture docs, CI examples
 ```
@@ -52,7 +52,7 @@ bash scripts/ralph_e2e_short_rp_test.sh
 
 All tests create temp directories and clean up after themselves. They must NOT be run from the plugin repo root (safety check enforced).
 
-**Storage runtime**: State is stored in JSON/JSONL files in the `.flow/` directory, readable by any tool. The `flowctl-db` crate provides synchronous file-based storage with no external database dependencies.
+**Storage runtime**: All state is JSON/JSONL files in `.flow/`, readable by any tool (MCP, Read, Grep). No database, no async runtime. The `json_store` module in `flowctl-core` handles all file I/O.
 
 ## Code Quality
 

docs/adr-guide.md

@@ -19,7 +19,7 @@ Use `docs/decisions/` with sequential numbering:
 
 ```
 docs/decisions/
-  ADR-001-use-libsql-for-storage.md
+  ADR-001-json-file-based-storage.md
   ADR-002-wave-checkpoint-execution-model.md
   ADR-003-teams-file-locking-protocol.md
 ```