Sideloaded titles: use ids Steam's create-shortcut accepts

On the Frame, Steam refused to register titles whose id had a hyphen
(fc-smoke-exe) with "missing/invalid arguments", and registered the same
program as FCSmokeProbe (headset smoke test, 2026-09-27, BUILD_ID
20260922.6101926). Valve's client only allows ^[A-Za-z_][A-Za-z0-9_.]+$.

title_id now makes ids of letters, digits and _, not starting with a
digit, 2 to 64 long; new installs are checked against that, while titles
already on the Frame are still listed, launched and removed. Steam's error
text is trimmed before it's quoted, and the "install it again with Steam
running" hint only follows a Steam-not-running error.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ui/frame_titles.py

@@ -35,7 +35,13 @@ PY = 'python3 ~/' + UTILS + '/'
 # devkit-steam is the trampoline file that switches SteamOS to a sideloaded client
 # (select_steam.sh); a folder there breaks Valve's devkit tools.
 RESERVED_IDS = ('steam', 'steamdeckard', 'steamvr', 'steamvrdeckard', 'devkit-steam')
-ID_RE = re.compile(r'^[A-Za-z0-9][A-Za-z0-9_-]{0,63}$')
+# Any title folder on the Frame we'll list, launch or remove: safe in a shell and a path.
+ID_RE = re.compile(r'^[A-Za-z0-9_][A-Za-z0-9_-]{0,63}$')
+# What a new install may use. Steam's create-shortcut refused "fc-smoke-exe" with
+# "missing/invalid arguments" and took the same program as "FCSmokeProbe" (headset
+# smoke test, 2026-09-27, build 20260922.6101926); Valve's client only allows
+# GAMEID_ALLOWED_PATTERN, ^[A-Za-z_][A-Za-z0-9_.]+$ (devkit_client/gui2). No dots here.
+NEW_ID_RE = re.compile(r'^[A-Za-z_][A-Za-z0-9_]{1,63}$')
 DIR_RE = re.compile(r'^/[A-Za-z0-9_./-]+$')
 
 # Zip limits: well above any real game, well below a zip bomb.
@@ -124,13 +130,15 @@ def _pe(f, head):
 
 
 def title_id(name):
-    """The Devkit Game id Steam shows as the title's name: [A-Za-z0-9_-], at most 64."""
-    s = re.sub(r'[^A-Za-z0-9_-]+', '_', str(name or '').strip())
-    s = re.sub(r'_+', '_', s).strip('_-')[:64].strip('_-')
+    """The Devkit Game id Steam shows as the title's name, in the form Steam accepts
+    (NEW_ID_RE): letters, digits and _, not starting with a digit, 2 to 64 long."""
+    s = re.sub(r'[^A-Za-z0-9]+', '_', str(name or '').strip()).strip('_')[:64].strip('_')
     if not s:
         raise FrameError('the title needs a name with some letters or digits')
-    if s.lower() in RESERVED_IDS:
-        s += '-game'
+    if s[0].isdigit():
+        s = '_' + s[:63]
+    if len(s) < 2 or s.lower() in RESERVED_IDS:
+        s += '_game'
     return s
 
 
@@ -653,7 +661,7 @@ def install_plan(plan, name=None, exe=None, runtime=None, progress=None):
 
 def _install(plan, step):
     gid = plan['id']
-    if not ID_RE.match(gid) or gid.lower() in RESERVED_IDS:
+    if not NEW_ID_RE.match(gid) or gid.lower() in RESERVED_IDS:
         raise FrameError(f'bad title id {gid!r}')
     step("Syncing Valve's devkit tools to the Frame", 0.02)
     ensure_utils()
@@ -683,8 +691,9 @@ def _install(plan, step):
         ssh(f'cat > {GAMES}/{gid}-framecontrol.json', input=json.dumps(meta, indent=1), timeout=30)
         registered = True                    # the files stay: Steam registers them once it's running
         if 'error' in reply:
-            raise FrameError(f"Uploaded, but Steam didn't register it: {reply['error']}. "
-                             "With Steam running on the Frame, install it again.")
+            err = str(reply['error']).strip().rstrip('.')
+            hint = ' With Steam running on the Frame, install it again.' if 'not running' in err else ''
+            raise FrameError(f"Uploaded, but Steam didn't register it: {err}.{hint}")
         step('Done', 1.0)
         meta.update(runtime_label=RUNTIMES[plan['runtime']]['label'], steam=str(reply.get('success', '')).strip())
         return meta