contract(issue#2): amend per Volva paraphrase — defaults, query, metadata

Volva's contract paraphrase round (thread 01KS4DTCW8CV) surfaced five
ambiguities; three are real contract-text gaps and addressed here.

1) tags/archived/name defaulting was inconsistent across prose, INV-002,
and STEP 6. open_questions said "defaulting to sensible None/empty",
INV-002 said "populated from the response item shape", STEP 6 said
`item.get("tags", []) if "tags" in item else None` (which collapses
absent and explicit-null into the same None branch while letting an
explicit [] pass through). Tightened to: tags is always list[str]
defaulting to [] for absent/null/empty in list items; archived is
always bool defaulting to False; name remains str | None (the only
field where None is a meaningful value). create_session always sets
list-only fields to their fixed defaults (name=None, archived=False,
tags=[]) instead of None to keep the dataclass shape uniform.

2) The include_archived_query test said "URL has no include_archived
param OR explicit false". STEP 2 prescribes "ADD include_archived='true'
iff include_archived" — the OR-clause weakened the test against the
prescribed behavior. Tightened to: default (include_archived=False)
asserts NO include_archived param at all, not an explicit false.

5) metadata's populated semantics: INV-001 said "populated from the
201 response", STEP 5 said body.get("metadata", {}) — two valid
readings (trust the spec vs defensive default). Aligned to the
defensive shape: INV-001 + INV-002 now explicitly state "defaults
to {} when absent" as spec-drift tolerance.

Volva flags #3 (exception .body sensitivity — truncation reduces
size not sensitivity) and #4 (assert for runtime validation — Python
-O disables) reviewed and kept as-is. Both are intentional carryovers
from issue #1's precedent: exception .body is for caller debugging
bound to 1024 bytes (caller's responsibility to not log raw); assert
chosen for fast-path validation, trading -O robustness for normal-mode
speed.

Drift check still clean — amendments don't touch the pinned issue
body, so prd: hashes remain valid.

persistent-memory.md

@@ -80,6 +80,7 @@ decision. Captures rationale that won't be obvious from code alone.
 - `[2026-05-21]` **Default issue-tracker labels seeded** (17 total). Sleipnir gating (`ready-for-agent`, `blocked-needs-contract`, `blocked-needs-dependency`), triage (`needs-triage`, `needs-architect-decision`, `needs-info`), type (`bug`, `enhancement`, `task`, `documentation`), resolution (`duplicate`, `wontfix`, `invalid`), Ratatoskr-specific area (`sse-client`, `tui`, `cli`, `observability`).
 - `[2026-05-21]` **`ratatoskr.sse_client` implemented via TDD against issue #1's contract.** 37 contract-listed tests authored + GREEN per the tracer-bullet vertical-slice ordering (`_parse_sse_id` → `stream_turn` → `reconnect_turn` → `cancel_turn`). Refactor pass extracted `_iter_events` helper to dedupe INV-002 + INV-003 + terminal-break logic across `stream_turn` and `reconnect_turn`; `expected_turn_id=None` vs `expected_turn_id=N` distinguishes the two entry-point semantics Volva surfaced. Notable choices made during implementation: (a) regex `^-?\d+$` pre-check in `_parse_sse_id` to reject whitespace before `int()` (Python's `int(" 3 ")` would silently strip — this kept the strict-no-whitespace test honest); (b) `_DropAfter` AsyncByteStream subclass in tests to simulate mid-stream `RemoteProtocolError`; (c) ToolResult.result and ToolStart.arguments typed as `Any` (server JSON varies); (d) ruff line-length=100 (per pyproject) forced some test docstrings to be tighter than v0 draft.
 - `[2026-05-21]` **Issue #2 + contract: `ratatoskr.sessions`.** Scope is narrow — `create_session` (POST /sessions) + `list_sessions` (GET /sessions, cursor-paginated) + shared `SessionInfo` and `SessionPage` frozen dataclasses. Bundles two endpoints in one contract because they share the response envelope shape; splitting would duplicate the dataclass. Bifrost binding (Worldtree issue #160), ephemeral sessions, `GET /sessions/{id}`, `PATCH`, `DELETE`, and `GET /sessions/{id}/messages` (history) are explicitly out of scope (codified in the contract's `## Out of scope` H2 — first contract in this repo to carry that section, so future Volva consults resolve cleanly via the default path instead of needing `--out-of-scope` overrides). `prd:` pinned to issue #2 body SHA `01fbbd52b6d90eb0` at `2026-05-21T04:45:06+00:00`; drift check clean. `dependencies:` lists issue #1 as a convention-dependency (no code import; same API-consumption posture).
+- `[2026-05-21]` **Volva paraphrase round on `docs/contracts/issues/2.contract.md`.** Volva flagged 5 ambiguities; operator approved amendments to 3 of them. (1) `tags`/`archived`/`name` defaulting semantics now explicit: `tags: list[str]` (default `[]`), `archived: bool` (default `False`), `name: str | None` (default `None`); INV-001/INV-002 + STEPS aligned. (2) `include_archived_query` test tightened: default → URL has NO `include_archived` param at all (was "no param OR explicit false" — softened the assertion against STEP 2's prescriptive behavior). (5) `metadata` populated-vs-defaulted slippage resolved: INV-001 + INV-002 now spell out the defensive `body.get("metadata", {})` default for spec drift tolerance. Volva flags #3 (exception `.body` sensitivity) and #4 (`assert` for runtime validation) reviewed and kept as-is — both intentional and consistent with issue #1's precedent. Drift check still clean (amendments don't touch the pinned issue body).
 - `[2026-05-21]` **Volva code-vs-contract review round on `ratatoskr.sse_client`.** Volva flagged 4 findings (3 drifts + 1 test-gap), all code-side "fix it" recommendations: (1) `_iter_events` fell off cleanly on EOF before terminal, violating INV-001 ("MUST NOT raise StopAsyncIteration before a terminal event arrives unless connection drops"); fix tracks `terminal_seen` flag and raises `SseConnectionDropped` on clean-EOF-without-terminal. (2) Both `SseConnectFailed.body` and `CancelFailed.body` stored full response bytes; ERROR_ROUTING specified truncation to `[:1024]`; fix truncates in `__init__` before storing. (3) `_parse_sse_id` PRE-001 specified `assert isinstance(raw, str)`, but code called `.split(":")` directly (incidental `AttributeError` on non-str); fix adds the assert. (4) Test-gap on cancel_turn's "other status → CancelFailed" branch; fix adds a 503 test with >1024-byte body that double-covers finding #2. Meta-note: Volva said TDD caught the main happy/adversarial shape; the misses were "negative space" cases (clean EOF, exception payload truncation, untested generic cancel branch) — calibration evidence that cross-model review pulls weight on the same-model author's blind spots. 43 tests GREEN post-fix (42 sse_client + 1 boundary), ruff clean.
 - `[2026-05-21]` **Volva paraphrase round on `docs/contracts/issues/1.contract.md`.** Volva flagged 5 ambiguities; operator approved amendments to 3 of them. (1) `reconnect_turn` STEP 2 punt resolved: signature now carries `content: str`; STEP 2 body is `json={"content": content}` matching spec §Reconnect flow example verbatim. Spec line 732 makes the agent's tools+LLM run "exactly once regardless of disconnects/reconnects" — the `content` is a wire-schema requirement, not re-processed server-side. (2) `_parse_sse_id` tightened: `turn_id ≥ 1` AND `seq ≥ 1` (was `≥ 0`); spec §SSE id format line 705 explicitly states `seq` starts at 1, and `turn_id` is SQLite autoincrement (≥1). Test `happy_zero_seq` flipped to `zero_seq [adversarial]`; new `zero_turn_id` + `negative_seq` adversarial tests added. (3) INV-003 clarified to spell out the two-entry-point semantics: `stream_turn` establishes `turn_id` from the first event (first event always yields); `reconnect_turn` parses the expected `turn_id` FROM `last_event_id` BEFORE the connection opens, so the first server event is already a flip-candidate and is NOT yielded on mismatch. Volva flags #3 (MalformedSseId-vs-ValueError split) and #5 (exactly-one-terminal as server-assumed) noted but kept as-is — deliberate distinctions. Drift check still clean against issue #1 (amending the contract doesn't touch the pinned issue body).