docs: align CLAUDE.md/AGENTS.md/README with the two-repo architecture; drop dead LLM routing

The LLM decision routing moved to the external Python backend
(OpenSquawk-LiveATC-api), but the core docs still described the old in-Nuxt
path (routeDecision(), /api/llm/decide, a Nuxt /api/decision-flows/runtime
route) — none of which exist. Every agent session started with a wrong mental
model.

- Rewrite CLAUDE.md to describe the real /pm flow (useRadioBackend -> Python
  backend owns authoritative state; Nuxt owns STT/TTS/audio/auth/editor) and
  fix stale commands (bun -> yarn).
- Fix the two stale AGENTS.md lines (openai.ts is getOpenAIClient() only;
  decisionFlowService is editor-only, no Nuxt runtime route).
- README: note the Python backend is required for /pm; correct server/ desc.
- Remove dead shared/utils/openaiDecision.ts (called the non-existent
  /api/llm/decide) and the now-orphaned LLM decision contract types in
  shared/types/llm.ts. Trace types used by pm.vue are kept.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

shared/types/llm.ts

@@ -1,15 +1,5 @@
 import type { DecisionNodeCondition, DecisionNodeTrigger } from './decision'
 
-export interface LLMDecisionInput {
-    state_id: string
-    state: any
-    candidates: Array<{ id: string; state: any; flow?: string }>
-    variables: Record<string, any>
-    flags: Record<string, any>
-    pilot_utterance: string
-    flow_slug?: string
-}
-
 export type FlowActivationMode = 'main' | 'parallel' | 'linear'
 
 export interface FlowActivationInstruction {
@@ -17,14 +7,6 @@ export interface FlowActivationInstruction {
     mode?: FlowActivationMode
 }
 
-export interface ActiveNodeSummary {
-    flow: string
-    state: string
-    role?: string
-    say_tpl?: string
-    controller_say_tpl?: string
-}
-
 export interface CandidateTraceEntry {
     id: string
     flow: string
@@ -81,17 +63,6 @@ export interface DecisionCandidateTimeline {
     autoSelected?: CandidateTraceEntry | null
 }
 
-export interface LLMDecision {
-    next_state: string
-    updates?: Record<string, any>
-    flags?: Record<string, any>
-    controller_say_tpl?: string
-    off_schema?: boolean
-    radio_check?: boolean
-    activate_flow?: string | FlowActivationInstruction
-    resume_previous?: boolean
-}
-
 export interface LLMDecisionTraceCall {
     stage: 'readback-check' | 'decision'
     request: Record<string, any>
@@ -116,10 +87,3 @@ export interface LLMDecisionTrace {
         reason?: string
     }
 }
-
-export interface LLMDecisionResult {
-    decision: LLMDecision
-    trace?: LLMDecisionTrace
-    active_nodes?: ActiveNodeSummary[]
-    pilot_intent?: string | null
-}