docs(evidence): publish curated-only workspace contract

docs/architecture/overview.md

@@ -46,6 +46,21 @@ Il modello propone; un revisore umano decide ai gate tramite widget:
 
 Il frontend renderizza questi widget-descriptor (registro in `src/widgets/`); il transcript live viene ricostruito in memoria dallo stream SSE (`src/store/sessionStore.ts`) — **non è persistito**.
 
+## Evidence curata e immutabile
+
+Il repository del workspace è il confine di pubblicazione: il curatore prepara `evidence/source/`,
+revisa le unità in `evidence/curated/`, valida e fa merge. Per `evidence.schema_version: 2` il
+runtime materializza l'intero albero `evidence/` dal commit Git esatto, ma il renderer consegna al
+preprocessing soltanto `curated/**/*.md` dalla root immutabile della revisione. Sorgenti, manifest
+ed evaluation restano disponibili solo per tracciabilità. Il runtime non modifica, stagea, committa
+o pubblica il repository di authoring.
+
+Prima dell'indicizzazione, il corpus curato della revisione pinnata viene validato. La collezione
+Qdrant condivisa conserva il vettore dense senza nome di Schema e Memory; il preprocessing Evidence
+può aggiungere soltanto in modo additivo il vettore sparse `bm25` con `idf`, senza eliminare,
+rinominare o ricreare la collezione. `workspace preprocess evidence` e la parte Evidence di
+`workspace preprocess run` sono le sole operazioni pubbliche che effettuano questo upgrade.
+
 ## Punti di attenzione ricorrenti
 
 - `tht -c`/`--config` è un'opzione **per-comando**: deve seguire il subcommand, mai precederlo (`ThtRunner.buildArgv` lo impone).

docs/contracts/workspace-evidence-v3.md

@@ -8,18 +8,40 @@ source variant and the policy reject unknown keys.
 ## Filesystem source
 
 A filesystem source uses the exact URI `<workspace.id>/evidence`. `patterns` is a nonempty list of
-unique, normalized relative POSIX globs. Its defaults are `patterns: ["**/*.md"]` and
+unique, normalized relative POSIX globs. The Evidence-local `schema_version` defaults to `1` for
+compatibility, where an omitted filesystem pattern defaults to `patterns: ["**/*.md"]` and
 `max_bytes: 10485760`.
 
+`evidence.schema_version: 2` declares the source/curated authoring layout. Its omitted filesystem
+pattern defaults to `patterns: ["curated/**/*.md"]`; every explicit v2 filesystem pattern must also
+remain below `curated/`. A v2 descriptor that selects `source/`, or spans both `source/` and
+`curated/`, is rejected. Explicit safe legacy filesystem patterns remain supported under Evidence
+version 1. HTTP and S3 sources do not use filesystem layout patterns and retain their existing
+contracts.
+
+The v2 authoring tree is:
+
+```text
+evidence/
+├── source/       # preserved original material
+├── curated/      # reviewed Evidence Units indexed at runtime
+├── manifest.yaml
+└── evaluation.yaml
+```
+
+`source/`, the manifest, the evaluation set, and other support files are materialized for
+traceability but never acquired by v2 runtime preprocessing.
+
 ### Example: filesystem
 
 ```yaml
 evidence:
+  schema_version: 2
   source:
     type: filesystem
     uri: example/evidence
     patterns:
-      - "**/*.md"
+      - "curated/**/*.md"
     max_bytes: 10485760
   policy:
     max_chunk_chars: 4000
@@ -152,8 +174,10 @@ catalog metadata exactly. Every catalog entry must have its descriptor at that s
 catalog-only entries are invalid and reject the complete candidate revision.
 
 Workspace source changes only through curator Git commit/push in a separate authoring clone,
-followed by an installation pull. The API never writes `thoth-workspaces.yaml`,
-`<id>/workspace.yaml`, `<id>/schema/**`, or `<id>/evidence/**`.
+followed by an installation pull. Curator validation occurs before merge; activation and
+preprocessing consume only the merged, pinned commit. The API and runtime never write
+`thoth-workspaces.yaml`, `<id>/workspace.yaml`, `<id>/schema/**`, or `<id>/evidence/**` in the
+authoring repository.
 
 ## Registry revision and phase ownership
 
@@ -164,7 +188,7 @@ followed by an installation pull. The API never writes `thoth-workspaces.yaml`,
 | Repository consumer | ThothII fetches and validates a complete candidate, atomically activates it only on success, and never edits, commits, or pushes repository content. |
 | Runtime secrets | Workspace management returns configured/missing status only; decrypted values exist only for the lifetime of a diagnostic or runtime lease. |
 | P1.1 | Validates the lexical URI `<id>/evidence` and proves the declared filesystem root object is a Git tree at that same commit; it does not recursively inspect nested symlinks. Evidence materialization stays out of scope for P1.1. |
-| P6 | Owns commit-addressed materialization, realpath and recursive containment, nested-symlink checks, and race checks. |
+| P6 | Owns commit-addressed materialization of the complete Evidence tree, realpath and recursive containment, nested-symlink checks, and race checks. |
 
 P1.1 performs no acquisition, extraction, preprocessing/indexing, embeddings, Qdrant writes,
 active-snapshot retention, or GC.

docs/contracts/workspace-preprocessing-cli.md

@@ -106,7 +106,13 @@ tht --installation <absolute>/thothii-installation.yaml workspace vector rebuild
   before any bytes are written and no partial root is published.
 - `preprocess evidence` and `preprocess run` operate directly on the materialized root; the
   temporary `evidence_materialization_required` stop is retired (the code remains only for
-  pre-P6 compatibility). HTTP/S3 Evidence is unchanged.
+  pre-P6 compatibility). For `evidence.schema_version: 2`, runtime acquisition receives only
+  `curated/**/*.md`; `source/` and support files remain in the materialized tree for traceability.
+  HTTP/S3 Evidence is unchanged.
+- The curator validates Evidence before merge. Preprocessing validates the pinned curated corpus
+  again before it constructs a candidate generation, so an invalid revision is never indexed.
+- The runtime writes only its immutable materialized snapshot and derived index state. It never
+  writes, stages, commits, or pushes the workspace authoring repository.
 - Materialized roots are retained with their commit-addressed snapshot directory and removed only
   when the revision becomes unreferenced.