fix(tui): tighten cold-start edge cases after review

Clean up the remaining review nits:

- let the deferred @hermes/ink import retry after a transient failure instead
  of memoizing a rejected promise forever
- keep memory-monitor in-flight state inside a finally so future exceptions
  cannot suppress that memory level indefinitely
- use read_raw_config for the TUI MCP cold-start probe instead of full
  load_config()
- keep input.detect_drop for explicit relative path prefixes (./ and ../)
  while preserving the no-RPC fast path for ordinary plain prompts

Tests:
- python -m py_compile tui_gateway/server.py tui_gateway/entry.py
- cd ui-tui && npm run type-check && npm run build
- scripts/run_tests.sh tests/tui_gateway/test_protocol.py::test_sess_found tests/tools/test_code_execution_modes.py tests/tools/test_code_execution.py
- cd ui-tui && npm test -- --run src/__tests__/useSessionLifecycle.test.ts src/__tests__/useConfigSync.test.ts

tui_gateway/entry.py

@@ -175,8 +175,8 @@ def main():
     # loaded once by ``_config_mtime`` elsewhere) and only pay the import
     # cost when there's actually MCP work to do.
     try:
-        from hermes_cli.config import load_config
+        from hermes_cli.config import read_raw_config
-        _mcp_servers = (load_config() or {}).get("mcp_servers")
+        _mcp_servers = (read_raw_config() or {}).get("mcp_servers")
         _has_mcp_servers = isinstance(_mcp_servers, dict) and len(_mcp_servers) > 0
     except Exception:
         # Be conservative: if we can't decide, fall back to the old

ui-tui/src/app/useSubmission.ts

@@ -127,9 +127,9 @@ export function useSubmission(opts: UseSubmissionOptions) {
       }
 
       // Plain prompts are the common path and should not pay an extra RPC
-      // before prompt.submit. File-drop detection can still run for inputs
+      // before prompt.submit. File-drop detection still runs for absolute,
-      // that contain an absolute/tilde path or file:// URI.
+      // tilde, file://, and explicit relative paths.
-      if (!looksLikeSlashCommand(text) && !/(?:^|\s)(?:file:\/\/|~\/|\/)[^\s]+/.test(text)) {
+      if (!looksLikeSlashCommand(text) && !/(?:^|\s)(?:file:\/\/|~\/|\.?\.\/|\/)[^\s]+/.test(text)) {
         return startSubmit(text, expand(text), showUserMessage)
       }
 

ui-tui/src/lib/memoryMonitor.ts

@@ -38,11 +38,16 @@ async function _ensureEvictInkCaches(): Promise<(level: 'all' | 'half') => unkno
     return _evictInkCaches
   }
 
-  _evictInkCachesPromise ??= import('@hermes/ink').then(mod => {
+  _evictInkCachesPromise ??= import('@hermes/ink')
+    .then(mod => {
       _evictInkCaches = mod.evictInkCaches as (level: 'all' | 'half') => unknown
 
       return _evictInkCaches
     })
+    .catch(err => {
+      _evictInkCachesPromise = null
+      throw err
+    })
 
   return _evictInkCachesPromise
 }
@@ -79,6 +84,7 @@ export function startMemoryMonitor({
     // Deferred import keeps `@hermes/ink` off the cold-start critical path;
     // by the time a tick fires 10s after launch the app has already loaded
     // the same module, so this resolves instantly from the ESM cache.
+    try {
       try {
         const evictInkCaches = await _ensureEvictInkCaches()
         evictInkCaches(level === 'critical' ? 'all' : 'half')
@@ -89,12 +95,12 @@ export function startMemoryMonitor({
 
       dumped.add(level)
       const dump = await performHeapDump(level === 'critical' ? 'auto-critical' : 'auto-high').catch(() => null)
-
-    inFlight.delete(level)
-
       const snap: MemorySnapshot = { heapUsed, level, rss }
 
       ;(level === 'critical' ? onCritical : onHigh)?.(snap, dump)
+    } finally {
+      inFlight.delete(level)
+    }
   }
 
   const handle = setInterval(() => void tick(), intervalMs)