feat(coach,admin): finish the self-context and invite surfaces end to end

Invites move into their own admin section with a real ledger: status
badges, expiry, uses, a redemption history of who joined when (new
redemption table, revocation is now soft so history survives), and an
honest one-time link/QR moment. The assistant self-context grows
structured fields for conditions, allergies and focus — encrypted like
the free text — merges age and gender from the profile into one fenced
prompt block, and asks up to three targeted follow-up questions that
surface as tappable chips above the coach composer. A fourth nudge
trigger gently suggests a check-up when the self-context is stale and
the coach is actually in use.

src/lib/validations/about-me.ts

@@ -1,5 +1,9 @@
 /**
  * v1.15.20 — request schema for `PUT /api/coach/about-me`.
+ * v1.16.0 — extended with three structured self-context fields
+ * (conditions, allergies, coach focus). Age/gender deliberately stay
+ * on the User profile and are merged into the prompt block at assembly
+ * time — the questionnaire never duplicates them.
  *
  * Lives outside the route file so the OpenAPI registry
  * (`src/lib/openapi/routes.ts`) can import it without touching the
@@ -12,6 +16,20 @@ import { z } from "zod/v4";
 /** Hard cap enforced BEFORE encryption. */
 export const ABOUT_ME_MAX_CHARS = 4000;
 
+/** Per-field cap for the structured answers, BEFORE encryption. */
+export const ABOUT_ME_FIELD_MAX_CHARS = 500;
+
+const structuredField = z
+  .string()
+  .max(
+    ABOUT_ME_FIELD_MAX_CHARS,
+    `Maximum ${ABOUT_ME_FIELD_MAX_CHARS} characters`,
+  )
+  // Optional so older clients that only send `aboutMe` keep working;
+  // an omitted field leaves the stored value untouched, an empty
+  // string clears it (mirrors the `aboutMe` semantics).
+  .optional();
+
 export const aboutMePutSchema = z.object({
   /**
    * The user's free-text self-description. An empty / whitespace-only
@@ -20,6 +38,12 @@ export const aboutMePutSchema = z.object({
   aboutMe: z
     .string()
     .max(ABOUT_ME_MAX_CHARS, `Maximum ${ABOUT_ME_MAX_CHARS} characters`),
+  /** Chronic conditions, short free text. */
+  conditions: structuredField,
+  /** Allergies / intolerances, short free text. */
+  allergies: structuredField,
+  /** What the Coach should pay attention to, short free text. */
+  coachFocus: structuredField,
 });
 
 export type AboutMePutInput = z.infer<typeof aboutMePutSchema>;