feat: wire Python backend session to PTT, add pm.vue debug logger

- Pass  as top-level field in PTT requests so Whisper STT
  results are linked to the correct Python backend session
- Add namespaced  helper in pm.vue (info/warn/error/debug/group)
  controlled by localStorage PM_DEBUG flag; logs transmit/response
  cycles, TTS calls, flag/variable syncs, and fallback warnings
- Log backend session creation context (flow, start state, vars, flags)
  in startMonitoring
- Fix typo in text input hint: STT fails not PTT fails

and

fix: sync backend variables to frontend after each transmission

The ATC say template was rendered using the frontend engine's local
variable defaults (squawk '1234', hardcoded SID, etc.) instead of
the authoritative values from the Python backend session. This caused
the spoken clearance and the readback prompt to show different squawk
codes.

- After each backend transmission response, sync all response.variables
  into vars.value (same pattern already used for flags)
- Prefer controller_say_rendered (pre-rendered by backend) over the raw
  template for TTS scheduling, eliminating any remaining dependency on
  local variable state for the ATC speech text

shared/utils/communicationsEngine.ts

@@ -295,8 +295,24 @@ export default function useCommunicationsEngine() {
     }
 
     function createSnapshotFromTree(treeData: RuntimeDecisionTree): FlowSnapshot {
-        const variables = { ...treeData.variables }
-        const baseFlags = (treeData.flags && typeof treeData.flags === 'object') ? { ...treeData.flags } : {}
+        // The Python backend serializes variables/flags as VariableDefinition/FlagDefinition objects
+        // ({ name, type, initial, mutable_by }) rather than raw values. Unwrap them here so
+        // template rendering gets the primitive value instead of [object Object].
+        const rawVars = treeData.variables ?? {}
+        const variables = Object.fromEntries(
+            Object.entries(rawVars).map(([k, v]) => [
+                k,
+                v !== null && typeof v === 'object' && 'initial' in v ? (v as any).initial : v,
+            ])
+        )
+        const rawFlags = treeData.flags ?? {}
+        const unwrappedFlags = Object.fromEntries(
+            Object.entries(rawFlags).map(([k, v]) => [
+                k,
+                v !== null && typeof v === 'object' && 'initial' in v ? (v as any).initial : v,
+            ])
+        )
+        const baseFlags = typeof unwrappedFlags === 'object' ? unwrappedFlags : {}
         const stack = Array.isArray((baseFlags as any).stack) ? [...(baseFlags as any).stack] : []
         const flags: EngineFlags = {
             in_air: Boolean((baseFlags as any).in_air),