chore(main): release 0.9.1

[cella-releases]

Automated release PR. Review the changelog below, then merge to cut the release.

0.9.1 (2026-08-14)

🎉 New features

• auth: carry post-auth deep-link redirect through magic link, OAuth and MFA (#1054) (e297a3c)

🐞 Bug fixes

• auth: create OAuth client auth lazily so empty secrets don't crash module load (#1053) (960c00f)
• backend: derive membership mock ancestor IDs from the channel row (#1048) (c2ef748)
• infra: boot-diag empty-bucket guidance and boot.log selection (#1049) (c73c84b)
• tests: adopt projectcampus fixes — hierarchy seeding, fixture parity, flaky cleanup (#1046) (be54736)

🔧 Small improvements

• auth: replace deprecated arctic and @oslojs packages (#1052) (837e570)
• blocknote: align UI adapter with @blocknote/shadcn 0.53 Base UI contract (#1055) (848d116)
• infra: shared iam-client + doc sweeps (teardown, vocabulary, credentials) (#1045) (5dc9921)

📖 Documentation

• cella: sync skill routes commit/ship through the CLI, never plain git (#1042) (5fe6e8d)
• skills: consolidate agent skills into cella/skills (#1043) (d4d080e)

🧹 Chores

• deps: minor/patch dependency sweep, hold @hono/zod-openapi at 1.5.1 (#1051) (a75b7f2)
• lint: clear comment-style backlog and make the style pass blocking (#1050) (93bbd15)

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This PR was generated with Release Please. See documentation.

[cella-releases]

🤖 Created releases:

• 0.9.1

🌻