chore(release): 0.90.0 - #669

Release PR for 0.90.0. Its only job is the version bump, the changelog entry, the vNEXT resolution and the What's new reel -- no behavior changes of its own.

Scope: every PR merged since v0.89.0

The 0.89.0 tag was cut at 2026-08-23 09:43 UTC; all ten of these landed after it.

Each has its own bullet in the changelog entry (13 bullets; #658 and #665 carry two each because they shipped separable things).

The one contract change worth calling out

ErrorCode.NOT_FOUND now answers HTTP 404 on every kbagent serve route (was 502, from #665). Any consumer branching on the status code alone needs updating. It is filed under Change: rather than BREAKING: because the documented contract has always been error.code, and that field is unchanged -- say the word if you want it reclassified.

Checklist (CONTRIBUTING > "Releasing a new version")

• 2. pyproject.toml -> 0.90.0
• 3. changelog.py: one entry, 13 bullets, every PR above referenced, each first sentence self-contained (test_newest_release_notes_are_not_truncated caught two over-long headlines; both rewritten)
• 4. vNEXT resolved. The release-checklist grep is intentionally NOT empty -- four hits survive and all four are prose about the placeholder mechanism, not version gates: CLAUDE.md:170,177,271 and docs/web-server.md:351. Every actual (since vNEXT) / vNEXT+ behavior gate is now 0.90.0.
• 5. make version-sync -> plugin.json, marketplace.json, uv.lock
• 6. make skill-gen -- no diff (no command signatures changed this release)
• 7. keboola-expert.md reviewed -- see below
• 8. gotchas.md reviewed -- the two vNEXT entries feat(ui): shareable deep links, rendered detail views, component-detail 502 fix #665/fix(component): omitted --project resolves to first configured project #666 left are now tagged 0.90.0; nothing else this release needs a new entry
• 9./10. CLAUDE.md command list + commands-reference.md -- no new commands or flags beyond serve --no-banner, which feat(serve,ui): what's-new popup with --no-banner opt-out #663 already documented in both
• 11. make check clean: 6029 passed, 12 skipped
• 12. make test-e2e -- not run here (needs E2E_API_TOKEN / E2E_URL). No CLI command signature changed this release, so the e2e surface is unchanged; run it if you'd rather not take that on faith.

Plugin / doc files touched (no CI coverage -- please eyeball)

• plugins/kbagent/.claude-plugin/plugin.json -- version (auto)
• .claude-plugin/marketplace.json -- version (auto)
• plugins/kbagent/skills/kbagent/references/gotchas.md -- vNEXT -> 0.90.0 (5 occurrences, 2 entries)
• plugins/kbagent/skills/kbagent/references/commands-reference.md -- vNEXT -> 0.90.0 (3 lines)
• plugins/kbagent/agents/keboola-expert.md -- one new inline gotcha (§3): component detail's Storage-catalog fallback always reports examples_count: 0, which reads as "this component ships no examples" when it actually means "this source carries none". Before feat(ui): shareable deep links, rendered detail views, component-detail 502 fix #665 the same call errored, so the wrong conclusion is new. 50 988 B of the 70 000 B budget.
• CLAUDE.md -- vNEXT -> 0.90.0 on the two behavior gates (lines 721, 968)
• docs/web-server.md -- vNEXT -> 0.90.0 on four behavior gates
• src/keboola_agent_cli/commands/context.py -- vNEXT -> 0.90.0 (2)
• web/frontend/src/whatsnew.ts -- new curated reel for 0.90.0, 7 items led by deep links and the storage-aware palette. Required by feat(serve,ui): what's-new popup with --no-banner opt-out #663's contract: without it whatsNewFor falls back to the 0.89.0 entry, whose seen-marker most users have already set, so the release would ship its UI work dark.

Verification

• make check -- 6029 passed, 12 skipped. Clean lint/format/typecheck/skill/version/version-gate/command-sync/changelog/error-codes/sentinel-guards/loc.
• Frontend gate (frontend.yml, new in ci: gate web/frontend PRs on tsc --noEmit + vite build #661) run locally in web/frontend: tsc --noEmit clean, vitest run 53 passed (3 files), vite build OK.
• kbagent changelog --limit 2 renders the 0.90.0 headline correctly.
• The ty unresolved-import warning on scripts/hatch_build.py:66 (hatchling not a dev dep) is pre-existing -- verified identical on main at this base; make typecheck exits 0.

After merge

Tag the resulting main commit and publish -- the pipeline renders the release notes from the changelog entry via scripts/gen_release_notes.py.