feat: P4 qdrant collection lifecycle (self-heal + guarded rebuild)

- shared TS collection manager: self-heal creates missing collection (1024/cosine)
  and missing keyword payload indexes; never mutates incompatible contracts
  (semantic_index_incompatible); async index visibility polled with bounded deadline
- session admission (qdrantEnsure) uses the manager in self-heal mode; operator path
  keeps require_existing semantics
- runtime lease exposes semanticQdrantUrl to the operator
- operator commands vector-inspect/vector-rebuild with exact confirmation guards
- thothctl workspace vector inspect|rebuild (Go) with --collection/--confirm/--destroy
- p4 acceptance runner: real Qdrant (v1.18.2) lifecycle checks, 11/11 PASS
- docs: CLI contract, manual walkthrough P4 (PENDING), PROJECT_STATE

docs/contracts/workspace-preprocessing-cli.md

@@ -29,6 +29,32 @@ thothctl --installation <absolute>/thothii-installation.yaml workspace preproces
 
 thothctl --installation <absolute>/thothii-installation.yaml workspace preprocess run
   --workspace <id> [--resume <32hex>] [--json]
+
+thothctl --installation <absolute>/thothii-installation.yaml workspace vector inspect
+  --workspace <id> [--json]
+
+thothctl --installation <absolute>/thothii-installation.yaml workspace vector rebuild
+  --workspace <id> --collection <name> --confirm <name> --destroy [--json]
+```
+
+## Qdrant collection lifecycle (P4)
+
+- `workspace vector inspect` reports the descriptor-owned Qdrant collection contract
+  (name, dimensions, distance, keyword indexes) **without mutation**.
+- `workspace vector rebuild` deletes and recreates the descriptor-owned collection
+  with the exact contract (1024 dimensions, cosine distance, the 8 required keyword
+  payload indexes) under guards:
+  - `--collection <name>` must equal the descriptor's `semantic_index.vector_store.collection`;
+  - `--confirm <name>` must equal `--collection` (exact repetition);
+  - `--destroy` is required to confirm the destructive operation;
+  - the operator refuses any other combination with exit code 2 (usage).
+- Self-heal at session admission: a missing collection is created and missing
+  keyword indexes are added by the shared collection manager; incompatible
+  dimensions/distance/index types are never mutated (`semantic_index_incompatible`).
+- The operator path (`workspace-maintenance.js vector-inspect|vector-rebuild`)
+  performs the guarded rebuild; rebuild state is written before deletion and the
+  collection is verified after recreation. No prefix matching or global Qdrant
+  mutation is performed.
 ```
 
 ## Validation