refactor(core): move ownership queries, import, and sync into idx-core

Phase 3c of docs/DESIGN.md. `ownership` handlers are now argument
parsing, one idx-core call, and rendering.

- investor.rs: Investor (also Idx::investor()) with releases, ticker,
  entity, search, cross_holders, concentration, flow, changes, graph,
  unresolved, map_alias, merge_entities, discover, sync, and import.
  Import orchestration (input resolution, download, SHA-256 dedup,
  PDF/XLSX/archive parsing, entity resolution, release write) moves
  from the CLI unchanged.
- Typed inputs: ImportSource, HolderSource, ConcentrationRank, and
  parse_report_family, with the same error messages.
- CoreConfig gains an ownership_db override; db::open_db_at opens an
  explicit path. idx-cli no longer depends on rusqlite, sha2, or ureq
  at runtime.
- Behavior note: an invalid `ticker --source` or `concentration --by`
  is now rejected before the database file is opened (and created);
  the error and exit code are unchanged.
- Fix: building idx-cli without the ownership feature no longer warns
  about the ownership-only `blue` style.

All 143 goldens unchanged; 170 core + 7 CLI unit tests and 62 CLI tests
pass; clippy clean for default, release, testing, and no-default
feature sets. Live A/B against main: 16/16 stocks identical; ownership
discover got IDX 403 on both (exit 4 vs 1 is the phase 1 change).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/ARCHITECTURE.md

@@ -5,7 +5,8 @@
 The repo is a Cargo workspace with one shared version:
 
 - `crates/idx-core` (library): the `Idx` entry point with `market()`,
-  `financial()`, and `analysis()` (cache policy and `Fetched<T>` in `client.rs`),
+  `financial()`, `analysis()`, and `investor()` (cache policy and `Fetched<T>` in
+  `client.rs`; ownership queries, import, sync, and discovery in `investor.rs`),
   providers (`api/`), `analysis/`, `cache`, `config` (`CoreConfig`),
   `ownership/` (SQLite, parsers, discovery, snapshot sync), `error`, and
   `runtime` (quiet/info/warn). It owns the shared test fixtures in
@@ -14,8 +15,8 @@ The repo is a Cargo workspace with one shared version:
   color resolution (`config.rs`, `IdxConfig`), and rendering (`output/`). Its
   `tests/` hold the CLI integration and golden output suites.
 
-Ownership import/sync orchestration still lives in
-`crates/idx-cli/src/cli/ownership.rs` until phase 3c of `docs/DESIGN.md`.
+`crates/idx-cli/src/cli/` holds no fetching, caching, or database logic: each
+command parses arguments, makes one idx-core call, and renders the result.
 
 ## Domain Map
 

docs/DESIGN.md

@@ -1,6 +1,6 @@
 # System Design: idx-core and its frontends
 
-**Status:** Accepted 2026-10-14. Implementation on `refactor/idx-core`; phases 0-2 done.
+**Status:** Accepted 2026-10-14. Implementation on `refactor/idx-core`; phases 0-3 done.
 
 ## Goal
 
@@ -119,8 +119,8 @@ Key decisions:
 | ownership command orchestration (`cli/ownership.rs`) | `investor` |
 | `IdxConfig.output`, `no_color` | stay in `idx-cli` |
 
-After the move, `cli/stocks.rs` and `cli/ownership.rs` should be argument
-parsing plus a call into core plus rendering.
+Done in phase 3: `cli/stocks.rs` and `cli/ownership.rs` are argument parsing,
+one idx-core call, and rendering.
 
 ## Error Model