feat(connectors): add managed file and PostgreSQL origins

README.md

@@ -14,12 +14,14 @@ or reporting behavior.
 
 ## Executable First Slice
 
-The first executable connector capability provides tenant-isolated tabular
-origins. Operators can import bounded JSON or CSV snapshots, inspect inferred
-schemas, and expose immutable source references and content fingerprints
-through `connectors.datasource_origins@0.1.0`. Preview reads enforce provider
-ceilings for rows, serialized bytes, and elapsed time and report the effective
-limits and any truncation as structured diagnostics.
+The executable connector capability provides tenant-isolated tabular origins.
+Operators can import bounded JSON or CSV snapshots, bind an exact managed Files
+CSV/XLSX version, or discover a table through an active governed PostgreSQL
+configuration. Every origin exposes a reviewed schema, opaque reference, and
+content/discovery fingerprint through `connectors.datasource_origins@0.1.0`.
+Preview reads enforce provider ceilings for rows, serialized bytes, and elapsed
+time and report the effective limits and any truncation as structured
+diagnostics.
 
 Connectors owns acquisition, connection profiles, credentials, discovery, and
 provider health. `govoplan-datasources` registers an origin as a governed live
@@ -29,12 +31,28 @@ connector implementations or stores connector credentials.
 
 Each origin declares whether it is live, cached, file-backed, or static, its
 structured health state, and which projection, filter, aggregation, sorting,
-and pagination operations it can push down. The immutable snapshot provider
-currently supports projection and pagination only; consumers must keep other
-operations in Dataflow rather than assuming transport-side execution.
+and pagination operations it can push down. The snapshot, managed-file, and
+PostgreSQL providers currently support projection and pagination only;
+consumers must keep other operations in Dataflow rather than assuming
+transport-side execution.
 
-Database, REST/HTTP, directory, managed-file, and warehouse providers can
-implement the same origin contract without changing Datasources or Dataflow.
+Managed-file sources are authorized and opened through
+`files.tabular_content@1.0.0`; Files remains authoritative for ownership,
+shares, download permission, exact versions, integrity, quarantine, encryption,
+retention, and legal holds. CSV must be UTF-8. XLSX input is protected by
+compressed-entry, expanded-byte, compression-ratio, row, and column limits.
+A newer current version is reported but never silently replaces the pinned
+version.
+
+The PostgreSQL adapter accepts only an active governed connector configuration
+whose secret-free endpoint uses the PostgreSQL driver. Authentication is
+resolved from a tenant/scope/module/server-restricted Core credential envelope.
+The adapter reflects a simple schema/table identifier, uses read-only
+transactions and a statement timeout, and blocks configuration, credential, or
+schema drift until an operator refreshes and reviews the source. Secrets are
+never copied into source metadata or diagnostics. Other database, REST/HTTP,
+directory, and warehouse providers can implement the same origin contract
+without changing Datasources or Dataflow.
 
 Governed sanctions and feed snapshot acquisitions use Core recovery operations.
 The source revision/cursor, redacted dry-run decision, canonical request digest,