Fix session cookie max-age bug; add UI hardening roadmap

Cookie max-age was 900s (15 min, matching access token) but refresh
token lives 7 days — users got bounced to login after 15 min idle
because the Go SSR middleware rejected the expired cookie before JS
could refresh. Now cookie max-age = 604800s (7 days) on both the
client (auth.js) and server (auth.go OIDC callback).

Go page-auth middleware accepts expired-but-signed JWTs via new
parseJWTIgnoringExpiry() so the page shell renders and the Preact SDK
can refresh client-side. API middleware still validates expiry strictly.
6 new middleware tests cover strict/lenient/tampered/garbage cases.

VERSION bumped to 0.6.8 (rebrand was already shipped but file missed).
ROADMAP-UI.md added with 7 milestones (v0.6.9–v0.6.15).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/handlers/auth.go

@@ -286,8 +286,10 @@ func (h *AuthHandler) OIDCCallback(c *gin.Context) {
 	refreshToken, _ := tokens["refresh_token"].(string)
 	userJSON, _ := json.Marshal(tokens["user"])
 
-	// Set page-auth cookie too (for SSR middleware)
-	c.SetCookie("arm_token", accessToken, 900, "/", "", false, false)
+	// Set page-auth cookie too (for SSR middleware).
+	// MaxAge = 7 days — matches refresh token lifetime so the cookie
+	// survives until JS can proactively refresh the access token.
+	c.SetCookie("arm_token", accessToken, 604800, "/", "", false, false)
 
 	// Base64-encode the token payload for the fragment
 	payload := fmt.Sprintf(`{"access_token":"%s","refresh_token":"%s","user":%s}`,