Evaluate the personal-data catalog: the data inventory and its history

Personal-data catalog spec, §6 (Phase 3c).

inbuxa:DataInventory/get evaluates the catalog against the server's
live settings and says what this server holds: for each source and each
object that can hold personal data, its categories and whose data it
is, whether it is collected here at all, what bounds its retention (the
live value of the setting that does, or unbounded), whether it leaves
the host and to which endpoints, and a summary. Every host that
receives something is listed once as a candidate processor with what it
receives. Inside a tenant it answers with the tenant's slice and none
of the server's processors. Read-only, with sysComplianceGet.

inbuxa:InventorySnapshot/get is the history: a dated copy of the
evaluated inventory, recorded when it changes -- after a registry write
to an object the inventory reads, after inbuxa's log, audit or AI
settings change, and on the daily clean-up -- and kept as long as the
audit log's records. ids: null lists every snapshot, newest first; the
full inventory only when asked for.

The catalog is embedded and parsed at start (new dependency: toml,
MIT/Apache); the evaluation is a pure function of it and the live
facts, so each configuration is tested without a server. Loopback
endpoints stay on the host; any other configured endpoint leaves it.

Tested: unit tests for the evaluation (a new install's defaults, an
external blob store, a hosted AI endpoint, telemetry off, a tenant's
slice, hosts from URLs, loopback), snapshots, and the fact gathering's
store and duration rules; the compliance system test, extended (the
officer reads the inventory, a plain user is refused, a tenant's
officer sees its slice and no processors, a webhook to another host
becomes a processor and a snapshot names x:WebHook, a retention change
reads through); the system, audit, legal hold and account lock suites;
fork checks. The system suite failed once of three runs with an email
import's blob not found, in antispam.rs; the same happened once in
purge.rs on the previous branch. Nothing here touches uploads; noted
for a separate look.

docs/spec/features/personal-data-catalog.md

@@ -497,6 +497,26 @@ leaving the host, processors), and on `get` the full inventory as above.
 Kept for `inbuxa:AuditSettings.keepForDays`, so history is as long as the
 audit log's. Same permission and tenant scoping as the inventory.
 
+### As built (2026-09-28)
+
+- The catalog is embedded and parsed at start
+  (`crates/features/src/privacy/`, `toml` crate); the evaluation is a pure
+  function of the catalog and the live facts, which
+  `crates/common/src/privacy.rs` gathers: retention settings, what is
+  switched on (tracers, webhooks, the classifier and its AI model, Explain,
+  DNSBL, Pyzor, milters, hooks, relays, archiving, report keeping), and
+  stores or endpoints off the host. Loopback endpoints stay on the host;
+  any other configured endpoint counts as leaving it.
+- Objects with nothing personal aren't listed. An object's categories are
+  the union of its properties'.
+- `inbuxa:InventorySnapshot` has `get` only: `ids: null` lists every
+  snapshot kept, newest first, and `inventory` is sent only when asked for
+  in `properties` (the `query` above folds into this).
+- A snapshot is recorded only when the evaluated inventory differs from
+  the newest one (or there is none): after a registry write to an object
+  the inventory reads, after inbuxa's log, audit or AI settings change, and
+  on the daily clean-up. Snapshots past the audit log's retention go then.
+
 ## 7. The compliance role
 
 ### What it holds