Docs: Update the Templates page for the new Share and Template tabs

[dataleaplabs-team]

What changed for the user

The Templates page told people to "hit Share" and showed a screenshot of the old Share popover. Since Use only sharing shipped, the Share dialog has two tabs — Share and Template — so the screenshot shows a UI that no longer exists and the step skips the tab switch and the Create Template button.

This PR:

• Rewrites step 1 of Create a template: click Share, the dialog opens on the Share tab, switch to the Template tab, click Create Template. Cross-links the Share tab to Use only.
• Adds a <Note> that Create Template is disabled until the agent has instructions (tooltip: "Add instructions to your agent before creating a template").
• Removes the stale /images/template-share-popover.png reference and leaves a TODO for the replacement screenshot.
• Aligns labels with the current UI: Name, Description, Setup Prompt, Regenerate, Template Link, Publish to Library, Manage Template, Update.
• Replaces the unverified "unpublished changes" wording with pending changes published via Manage Template → Update.

Nothing else on the page changed. The three template-wizard screenshots are untouched.

Prompted by

• Simon in #docs-ideas (2026-08-21): the sharing screenshots are outdated because sharing logic changed with Use only; confirmed in-thread that the stale ones are on the Templates page.
• Source product PR: https://github.com/dataleap-labs/tahoe/pull/663 (Use only sharing)

Source verification

Every claim above was read from the current product source on main:

• share-agent-content.tsx — the Share dialog is a two-tab layout, Share (default) and Template.
• share-agent-template-section.tsx — Create Template / Manage Template buttons, the disabled-state tooltip, template link + copy.
• template/type/index.tsx — "How should this be shared?" with Template and Locked Template cards.
• template/about.tsx — Name, Description, Setup Prompt ("Tells the AI how to guide users through setup"), Regenerate.
• template/publishing/index.tsx + publishing-settings-panel.tsx — Template Link, Copy Link, Publish to Library, destination picker (your organization or a single team), Publish / Update.
• template-builder-step-shell.tsx — the indicator reads "No pending changes"; there is no "unpublished changes" label.

Files changed

• share/templates.mdx

Needs confirmation

• Replacement screenshot for step 1. I need a PNG of the Share dialog on the Template tab (agent not yet shared as a template, so Create Template is visible). I cannot take product screenshots.
• Are the three wizard screenshots still current? template-wizard-type.png, template-wizard-about.png, template-wizard-publish.png were added in July, before Use only shipped. The wizard code has not obviously changed, but I cannot verify what the images show. Replace them if they are stale.
• Wording of step 1. Is "The dialog opens on the Share tab" the right level of detail, or should the page just say "open the Template tab"?
• Publishing destinations. The picker lists your organization and your teams; the toggle description says "your workspace library". I wrote "your whole organization or a single team" — confirm that matches what users see.
• /images/template-share-popover.png is now unreferenced. Delete it in this PR, or keep it until the replacement lands?

Draft — not for merge until Simon reviews the Mintlify preview and says push.