fix(mode): explain stale cloud storage migration

[andrei-hasna]

Summary

• keep removed cloud mode values invalid instead of reintroducing the removed placement axis
• tell operators to unset the stale mode variable for the default sqlite backend, or select sqlite/postgres explicitly
• add exact CLI regressions for the default convention read and explicit sqlite control

Root cause

The live @hasna/knowledge CLI already defaults to sqlite when no mode variable is present. The failure came from an obsolete ambient HASNA_KNOWLEDGE_STORAGE_MODE=cloud export after the placement vocabulary was removed.

Verification

• bun test
• bun run build
• bun run test:package
• bun run release:pack:check
• bun run verify:generated
• clean candidate exact default command: rc 0, ok: true
• explicit HASNA_KNOWLEDGE_STORAGE_MODE=sqlite: rc 0, ok: true
• staged secret scan: no findings in the changed hunks; workspace scan findings are pre-existing redacted fixtures/runtime references
• adversarial self-review: zero concrete reachable in-scope P0/P1 defects

Task: 46191ea9-f68a-48cd-85d0-45494b848041

No merge, publish, production install, deploy, or production mutation performed.

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[andrei-hasna]

[REVIEW] GO — #72 @ 01ce5a7 — lens: correctness+security+gates, reviewer Xenon (1 of 1)

Reviewed the exact candidate against the freshly fetched base: origin/main at 5cc02ee78edde7b333a07b9799a70a871c7bee9c. I read git log --oneline origin/main..HEAD, the full diff and stat, every changed source/test/generated file, and surrounding code in src/knowledge-mode.ts, src/cli.ts, tests/cli.test.ts, tests/knowledge-mode.test.ts, the generated-artifact verifier, package.json, and the CI workflow. The minified CLI, MCP, and library artifacts were checked through the repository's byte-identical rebuild gate.

Commands and results:

• bun install — exit 0. Setup only, not a test gate; 156 packages installed.
• bun run test — exit 0. 437 pass, 0 fail, 2 skip; 439 tests across 49 files.
• bun run verify:generated — exit 0. Six generated bundles rebuilt byte-identically; zero stale-generated-code findings.
• This repository declares no standalone typecheck script; none was invented.

Blocking P0/P1 findings: none.

Non-blocking follow-ups: none.