chore: rename packages/ to crates/

Move all 29 workspace members from packages/<name>/ to crates/<name>/.
Updates: workspace Cargo.toml (members + path deps), justfile, root
CLAUDE.md, scripts/build/CARGO_INSTALL.md, docs/architecture/crates.md
(renamed from packages.md), structural references in docs/architecture
and docs/configuration, per-crate CLAUDE.md self-references. Historical
plans, reports, and building/ docs are left untouched.

No behavior change; just check-all stays green and fermata tests pass.

CLAUDE.md

@@ -0,0 +1,34 @@
+# Package: dirigent_fermata
+
+Harness-agnostic policy gate for AI coding agents.
+
+## Quick Facts
+- **Type**: Library + binary (`fermata`)
+- **Main Entry**: `src/lib.rs`, `src/bin/fermata.rs`
+- **Dependencies**: `ignore`, `toml`, `regex`, `globset`, `serde`, `clap` (cli feature)
+- **Status**: v0.1 — library + CLI + Claude hook adapter
+
+## Layering
+
+Three concentric layers; nothing inner imports from anything outer.
+
+- **`core/`** — harness-unaware, transport-unaware, sync. Types (`Op`, `Decision`), `.botignore` walker, `botignore.toml` parser, `Policy::check` / `check_command`, path extraction. Sync, no tokio.
+- **`harness/`** — `HarnessAdapter` trait over a normalized `ToolCall`. Each adapter (Claude, future Codex, etc.) lives in its own submodule, feature-gated.
+- **`bin/fermata.rs`** — only place where `clap`, stdio, and exit codes appear.
+
+## Release Model
+
+Developed in this monorepo; planned to be exported as a standalone repo in the future for advertising / external distribution. Development stays here. See `docs/tools/fermata.md`.
+
+## Dependency Direction
+
+`dirigent_tools` depends on `dirigent_fermata`, never the reverse. Fermata must remain usable as a standalone hook/MCP without dragging in the in-process ACP tool runtime.
+
+## Out of scope (v0.1)
+
+Codex / Gemini hook adapters, MCP server mode, PostToolUse envelope, `readonly_only` Bash mode, audit log, filesystem watcher. Each is a future task with its own plan.
+
+## See also
+
+- `docs/tools/fermata.md` — Dirigent integration plan
+- `docs/workpad/brainstorm/fermata.md` — canonical product spec