Viral welcome tour + line banner + wall, milestone stepper, rich solo editor, CTA-gated reads

- Welcome tour (3 levels x 10s) unlocks welcome credits; line banner in Profile; public /wall/<username>
- 'Your next move' redesigned as a milestone stepper
- Solo composer: BV-style rich editor (H2/H3, inline image+video, undo/redo, raw text)
- Solo read reward now requires clicking through to the advertiser, not just dwelling
- Sanitizer: inline media whitelist + script/style stripped whole

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

db.js

@@ -79,6 +79,8 @@ async function bootstrap() {
   await alterSafe('ALTER TABLE accounts ADD UNIQUE KEY uq_username (username)');
   await alterSafe('ALTER TABLE accounts ADD COLUMN member_id INT NULL');
   await alterSafe('ALTER TABLE accounts ADD KEY idx_member (member_id)');
+  await alterSafe('ALTER TABLE accounts ADD COLUMN line_banner_url VARCHAR(500) NULL');
+  await alterSafe('ALTER TABLE accounts ADD COLUMN line_target_url VARCHAR(500) NULL');
   await q(`CREATE TABLE IF NOT EXISTS daily_views (
     email VARCHAR(190) NOT NULL,
     day CHAR(10) NOT NULL,
@@ -93,11 +95,13 @@ async function bootstrap() {
     email VARCHAR(190) NOT NULL,
     delivered BIGINT NOT NULL,
     read_ts BIGINT NULL,
+    visited_ts BIGINT NULL,
     rewarded TINYINT NOT NULL DEFAULT 0,
     rewarded_day CHAR(10) NULL,
     UNIQUE KEY uq_solo (campaign_id, email),
     INDEX (email), INDEX (email, rewarded, rewarded_day)
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);
+  await alterSafe('ALTER TABLE solo_inbox ADD COLUMN visited_ts BIGINT NULL');
   // solo message bodies are sanitized rich text; TEXT gives them room
   await alterSafe('ALTER TABLE campaigns MODIFY body TEXT NULL');
   await alterSafe('ALTER TABLE campaigns ADD COLUMN cta_label VARCHAR(40) NULL');