Replace self-service checkout with a needs form and booking step

[spashii]

Self-service checkout is replaced by a needs form and a booking step. A person who reaches a plan limit answers a few questions and books a call; existing subscribers keep managing their subscription.

Draft. Translations, analytics capture and a final walkthrough are still open. See the list at the end.

What changes for a person

• Blocked controls stay visible. Clicking one opens a small popover that names the feature, with one button, Tell us what you need. The standing "Available on a paid plan" boxes are gone.
• One modal from every mount point. Step 1 names what the person tried and says a few questions follow and end in a booking step. Then: what for, when, recordings in the first year, conversations at the busiest moment, anything else you might need. Nothing is required; skip is real; a reload restores the answers; the step lives in the url so the back button undoes a step.
• Every free text box has voice input through the existing composer where a transcription context exists.
• The booking step embeds cal.com with a reference and a plain summary of the answers prefilled. If the embed does not load within 8 seconds, a plain link takes over with the same information.
• The confirmation says the call is booked only after cal.com confirms it; otherwise it asks the person to check their mail. The mail link carries the reference in its subject.
• Billing page: an existing subscriber keeps plan, amounts, invoices, cancel and resume. A managed account keeps its panel. A free account sees no checkout and the same form entry. No new subscription can be started from the app.
• Documentation describes plan capabilities and directs pricing questions to the contact flow.
• User-facing copy was refreshed.

What changes underneath

• Directus, additive only: one new collection pricing_configuration, one idempotent migration in echo/directus/migrations/, the snapshot carries it. No existing field or collection is changed.
• API: POST /api/v2/pricing-configurations, upsert on config_session_id. Identity fields are derived server side; answers are saved before optional audio, and storage failures are reported separately. 16 tests.
• CSP (frontend/vercel.json): app.cal.com and cal.com in frame-src, script-src, connect-src and font-src, for the embed.
• Events: analytics hooks are wired; capture is not enabled in this PR.

Deployment

Apply the additive schema change before deploying. The frontend calls the new endpoint on its final step; if the frontend lands before the API, that step retries until the API is up, and nothing is lost.

Checks

• Frontend: tsc, biome lint, vite build, vitest for the pricing, workspace and billing components. Two failures in useChunkAnchorScroll.test.tsx predate this branch (missing jsdom directive).
• Server: ruff, tests/test_pricing_configurations.py. The migration is idempotent (second run is a no-op); upsert and access guards verified against a local stack.
• Existing billing surfaces verified unchanged for paying, managed, free and cancelled accounts.
• Catalogues extracted and compiled.

Still open before this leaves draft

• Dutch translations for the new strings remain under review; other locales fall back to English.
• Analytics capture.
• Voice input where no transcription context is present.
• The create-workspace access step still uses the old disabled state instead of the popover.
• A live check of the cal.com embed on the preview deployment.