…meters (#22011)

### Summary

Workspace created via mode=auto links now require explicit user
confirmation before provisioning. A warning dialog shows all prefilled
param.* values from the URL and blocks creation until the user clicks
`Confirm and Create`. Clicking `Cancel` falls back to the standard form
view.

<img width="820" height="475" alt="auto-create-consent-dialog"
src="https://github.com/user-attachments/assets/8339e3bd-434f-4a04-9385-436bf95f49d7"
/>

### Breaking behavior change

Links using `mode=auto` (e.g., "Open in Coder" buttons) will no longer
silently create workspaces. Users will now see a consent dialog and must
explicitly confirm before the workspace is provisioned. Any existing
integrations or automation relying on `mode=auto` for seamless workspace
creation will now require manual user interaction.

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Co-authored-by: Jake Howell <jacob@coder.com>
(cherry picked from commit 60e3ab7)

f0ssel deleted the cherry-pick/2.29/60e3ab7 branch