Cherry-picks #1582, #1583, #1584 and #1585 from @Sravanjangam (security audit #1578) onto one branch.
- MCP: `get_document` scopes to the active space like its sibling read tools, `fetch-graph-data` bounds page/limit, `guided-save` caps prefill at 200k, and `whoAmI` no longer returns the transport session id.
- ai-sdk: search limit clamped to 1-50 with a 30s client timeout.
- validation: caps on `DocumentsWithMemoriesQuerySchema.limit` and `BulkDeleteMemoriesSchema.containerTags`.
- Raycast: `metadata.url` is parsed and only http(s) is offered to the OS opener.
Dropped his `add_memory` permission gate: it checked the target against the list of existing spaces, so writes to a new space failed and the no-active-space path surfaced `No write access to space "undefined"`. Write permission stays enforced in the API via `containerTagGate`.
Hardening and consistency rather than a security fix, since the API already enforces every permission boundary here.
Co-Authored-By: Sravanjangam <163002695+Sravanjangam@users.noreply.github.com>
