fix(ci): repair release-root regressions — pack dedup, web-session syntax, uc-image ids (#12423)

Three regressions inherited by every PR rebased onto release/v3.8.51, caught and documented with the exact failing output.

The one that mattered most: src/shared/providers/webSessionCredentials.ts did not parse. The UC merge (#11513) inserted the uc: entry inside maxai.storageKeys and lost the array's closing ], plus the entry's }, leaving `ERROR: Expected "]" but found ":"` at line 351. That module is imported by the provider API routes, bulk-web-session, autoCombo's virtualFactory, keepaliveThreshold and dashboard components, so the break was live on the tip and flooded unrelated catalog tests with transform failures. That was my conflict resolution, not the contributor's code — thank you for catching it and for tracing it to the root commit rather than patching around the symptom.

Also fixed: the duplicate bin/cli/utils/volatileEnvPath.mjs entry in PACK_ARTIFACT_REQUIRED_PATHS (findMissingArtifactPaths reported it twice), and UC image models made prefix-addressable without letting them claim historical bare model ids belonging to other providers.

Reconciled on merge: #12394 landed the busy_timeout/probe work first, so src/lib/db/core.ts takes the tip's side. probeUtils.ts is the union of both rather than either side — this PR's message regex is wider (SQLite also reports "database table is locked", "database schema is locked" and "database is busy"), while #12394 added the driver code/errcode path that keeps a transient lock from being classified as corruption and renaming the database away. Taking either alone would have dropped the other half; this PR's own ENOENT test is what surfaced it.

Verified: 76/76 across uc-image, probe-9541-repro, web-session-contract, pack-artifact-policy, bulk-web-session-import and exclusive-connection-leases, and every changed .ts file parses.

Thanks @backryun.