policy: reject out-of-range seed boundaries; carry baselines through session-query

Review fixes (ds-review-bot on #623):

- overrideOf (both knobs) rejects a seedLength past the log end before
  slicing: a malformed durable boundary would otherwise empty the
  own-switch slice until the log outgrew it, letting a wide baseline
  shadow a REAL later tightening. Malformed durable metadata fails loud,
  never open.
- The session-query derived index carries the two baseline fields end to
  end: schema columns on both session tables (SESSION_QUERY_SQLITE_SCHEMA
  _VERSION 6 — derived, rebuilds in place), inserts, header selects, the
  candidates CTE, rowHeader, sameHeader, and the cross-source
  assertSessionHeadersCompatible — so a search hit's header keeps the
  child's inherited confinement and conflicting live/persisted baselines
  reject.

Red-first: out-of-range seedLength tests in both policy suites;
baseline round-trip and live/persisted baseline-conflict tests in the
session-query sqlite suite.

packages/session-query/session-query-sqlite/src/schema.ts

@@ -5,7 +5,7 @@ import { mkdir, open } from 'node:fs/promises'
 import { dirname, resolve } from 'node:path'
 
 /** Current derived-index schema version. Incompatible versions reset in place. */
-export const SESSION_QUERY_SQLITE_SCHEMA_VERSION = 5
+export const SESSION_QUERY_SQLITE_SCHEMA_VERSION = 6
 
 /** SQLite application id protecting unrelated databases from derived resets. */
 export const SESSION_QUERY_SQLITE_APPLICATION_ID = 0x44534851
@@ -117,6 +117,8 @@ function ensurePersistentSchema(db: DatabaseSync): void {
       parent_session TEXT,
       seed_length    INTEGER,
       delegation_depth INTEGER,
+      sandbox_mode   TEXT,
+      approval_policy TEXT,
       revision       TEXT NOT NULL,
       generation     INTEGER NOT NULL
     ) STRICT
@@ -146,6 +148,8 @@ function ensureTemporarySchema(db: DatabaseSync): void {
       parent_session TEXT,
       seed_length    INTEGER,
       delegation_depth INTEGER,
+      sandbox_mode   TEXT,
+      approval_policy TEXT,
       fingerprint    TEXT NOT NULL,
       persisted      INTEGER NOT NULL CHECK (persisted IN (0, 1)),
       generation     INTEGER NOT NULL