ux: chat header + greeting + brain avatar + share button + terms + badge

Restores inline-JS styles.el (the obfuscated /assets/js/*.js path
broke the chat widget) and threads four UX fixes through it:

  - Chat header: drop the all-caps "NEURON / Live Demo" subtitle, keep
    just "Neuron" in bold white at 1rem.
  - Greeting: replace the canned "Hi. I am Neuron. You get 5 questions"
    with "Hey. What is on your mind?" in all three callsites (open,
    reset, turnstile-verified). The questions counter is already in
    the header, so we don't need to repeat it.
  - Avatar: switch chat avatar from neuron-icon.png to the brain mark
    (/assets/brand/neuron-brain.png). Thinking state now shows the
    pulsing brain plus three-dot animation instead of "thinking..."
    text.
  - Share button: from a muted t3 link to a navy pill with subtle
    background, uppercase letter-spacing, and active-press feedback.

main.el: drop the FOUNDING_SOLD = 47 floor and rewrite
fetch_founding_count_stripe to count succeeded PaymentIntents (the
live Stripe Elements path) AND legacy Checkout Sessions, excluding
refunded charges.

founding_badge.el: rewrite to the Option C "Tag" design picked from
/tmp/founding-badge-preview.html - tall card, navy top stroke, brain
mark prominent, "Neuron, LLC" footer.

terms.el: kill the "Neuron Inference - our own inference layer, live
now" claim. Inference launches Q3 2026 and the wording now says so.

src/main.el

@@ -49,7 +49,7 @@ from account         import { account_page }
 // ── Founding counter ──────────────────────────────────────────────────────────
 
 let FOUNDING_TOTAL: Int = 1000
-let FOUNDING_SOLD:  Int = 47  // floor — real count comes from Stripe at startup
+let FOUNDING_SOLD:  Int = 0   // no artificial floor - real count comes from Stripe
 
 // ── Founding count helpers ─────────────────────────────────────────────────────
 
@@ -76,35 +76,48 @@ fn fetch_founding_count_stripe(stripe_key: String) -> Int {
     if str_eq(stripe_key, "") {
         return FOUNDING_SOLD
     }
-    // Fetch all complete checkout sessions and count founding ones.
-    // Note: metadata[] filter in URL causes 400 — filter client-side instead.
-    let url: String = "https://api.stripe.com/v1/checkout/sessions?status=complete&limit=100"
-    let resp: String = http_get_auth(url, stripe_key)
-    if str_eq(resp, "") {
-        return FOUNDING_SOLD
-    }
-    let data_raw: String = json_get_raw(resp, "data")
-    if str_eq(data_raw, "") {
-        return FOUNDING_SOLD
-    }
-    // Count only sessions where metadata.plan = "founding"
-    // json_get uses literal key search, so extract metadata object first
-    let total: Int = json_array_len(data_raw)
     let count: Int = 0
-    let idx: Int = 0
-    while idx < total {
-        let session: String = json_array_get(data_raw, idx)
-        // json_get_raw handles multi-line JSON; json_get stops at newlines
-        let metadata: String = json_get_raw(session, "metadata")
-        let plan: String = if str_eq(metadata, "") { "" } else { json_get(metadata, "plan") }
-        if str_eq(plan, "founding") {
-            let count = count + 1
+
+    // 1) PaymentIntents (Stripe Elements path - this is what the live site uses)
+    let pi_url:  String = "https://api.stripe.com/v1/payment_intents?limit=100"
+    let pi_resp: String = http_get_auth(pi_url, stripe_key)
+    let pi_data: String = if str_eq(pi_resp, "") { "" } else { json_get_raw(pi_resp, "data") }
+    if !str_eq(pi_data, "") {
+        let pi_total: Int = json_array_len(pi_data)
+        let pi_idx:   Int = 0
+        while pi_idx < pi_total {
+            let pi: String = json_array_get(pi_data, pi_idx)
+            let status: String = json_get(pi, "status")
+            let metadata: String = json_get_raw(pi, "metadata")
+            let plan: String = if str_eq(metadata, "") { "" } else { json_get(metadata, "plan") }
+            // Count only fully-charged founding PIs that are not refunded
+            let amt_refunded: String = json_get(pi, "amount_refunded")
+            let refunded_n: Int = str_to_int(amt_refunded)
+            if str_eq(status, "succeeded") && str_eq(plan, "founding") && refunded_n <= 0 {
+                let count = count + 1
+            }
+            let pi_idx = pi_idx + 1
         }
-        let idx = idx + 1
     }
-    if count <= 0 {
-        return FOUNDING_SOLD
+
+    // 2) Hosted Checkout Sessions (legacy /api/checkout path - kept for completeness)
+    let cs_url:  String = "https://api.stripe.com/v1/checkout/sessions?status=complete&limit=100"
+    let cs_resp: String = http_get_auth(cs_url, stripe_key)
+    let cs_data: String = if str_eq(cs_resp, "") { "" } else { json_get_raw(cs_resp, "data") }
+    if !str_eq(cs_data, "") {
+        let cs_total: Int = json_array_len(cs_data)
+        let cs_idx:   Int = 0
+        while cs_idx < cs_total {
+            let session: String = json_array_get(cs_data, cs_idx)
+            let metadata: String = json_get_raw(session, "metadata")
+            let plan: String = if str_eq(metadata, "") { "" } else { json_get(metadata, "plan") }
+            if str_eq(plan, "founding") {
+                let count = count + 1
+            }
+            let cs_idx = cs_idx + 1
+        }
     }
+
     return count
 }