feat(admin): inline term creation in post editor sidebar

[all3f0r1]

What does this PR do?

Adds inline term creation directly from the post editor's taxonomy sidebar, so users don't have to leave the editor to create new categories or tags.

• Tags (flat taxonomies): When the typed name has no exact match, a "Create [name]" option appears in the dropdown. Pressing Enter when it's the only option creates the tag.
• Categories (hierarchical taxonomies): An "Add new category" button appears below the checkbox list. Clicking it reveals an inline input field.

Both flows auto-select the newly created term and save immediately.

Closes #229

Type of change

• Bug fix
• Feature (requires approved Discussion)
• Refactor (no behavior change)
• Documentation
• Performance improvement
• Tests
• Chore (dependencies, CI, tooling)

Checklist

• I have read CONTRIBUTING.md
• pnpm typecheck passes
• pnpm --silent lint:json | jq '.diagnostics | length' returns 0
• pnpm test passes (or targeted tests for my change)
• pnpm format has been run
• I have added/updated tests for my changes (if applicable)
• I have added a changeset (if this PR changes a published package)
• New features link to an approved Discussion: https://github.com/emdash-cms/emdash/discussions/...

AI-generated code disclosure

• This PR includes AI-generated code

Screenshots / test output

UI-only change in the admin taxonomy sidebar. No new tests — this wires up the existing createTerm API to the sidebar components.

[changeset-bot]

🦋 Changeset detected

Latest commit: 7755497

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 9 packages

Name	Type
emdash	Patch
@emdash-cms/cloudflare	Patch
@emdash-cms/plugin-ai-moderation	Patch
@emdash-cms/plugin-atproto	Patch
@emdash-cms/plugin-audit-log	Patch
@emdash-cms/plugin-color	Patch
@emdash-cms/plugin-embeds	Patch
@emdash-cms/plugin-forms	Patch
@emdash-cms/plugin-webhook-notifier	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@emdash-cms/admin

npm i https://pkg.pr.new/@emdash-cms/admin@500

@emdash-cms/auth

npm i https://pkg.pr.new/@emdash-cms/auth@500

@emdash-cms/blocks

npm i https://pkg.pr.new/@emdash-cms/blocks@500

@emdash-cms/cloudflare

npm i https://pkg.pr.new/@emdash-cms/cloudflare@500

emdash

npm i https://pkg.pr.new/emdash@500

create-emdash

npm i https://pkg.pr.new/create-emdash@500

@emdash-cms/gutenberg-to-portable-text

npm i https://pkg.pr.new/@emdash-cms/gutenberg-to-portable-text@500

@emdash-cms/x402

npm i https://pkg.pr.new/@emdash-cms/x402@500

@emdash-cms/plugin-ai-moderation

npm i https://pkg.pr.new/@emdash-cms/plugin-ai-moderation@500

@emdash-cms/plugin-atproto

npm i https://pkg.pr.new/@emdash-cms/plugin-atproto@500

@emdash-cms/plugin-audit-log

npm i https://pkg.pr.new/@emdash-cms/plugin-audit-log@500

@emdash-cms/plugin-color

npm i https://pkg.pr.new/@emdash-cms/plugin-color@500

@emdash-cms/plugin-embeds

npm i https://pkg.pr.new/@emdash-cms/plugin-embeds@500

@emdash-cms/plugin-forms

npm i https://pkg.pr.new/@emdash-cms/plugin-forms@500

@emdash-cms/plugin-webhook-notifier

npm i https://pkg.pr.new/@emdash-cms/plugin-webhook-notifier@500

commit: 7755497