feat(ai): SSE streaming for foreground Mission Runner

Enable real-time token streaming during the planner "calling-llm" phase
so the user sees live progress ("empfange Plan… 128 tokens") instead of
a static spinner. The parser still receives the full text once complete —
no partial-JSON risk.

Changes:
- Extract shared SSE parser from playground into @mana/shared-llm/sse-parser
- remote.ts: use stream:true when onToken callback is provided
- AiPlanInput: add optional onToken field (shared-ai)
- ai-plan task: pass onToken through to backend.generate()
- runner.ts: throttled (500ms) phaseDetail updates during streaming
- Playground: refactored to use shared SSE parser

Also includes: AI agent architecture comparison report (docs/reports/)

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

packages/shared-ai/src/planner/types.ts

@@ -30,6 +30,13 @@ export interface AiPlanInput {
 	readonly mission: Mission;
 	readonly resolvedInputs: readonly ResolvedInput[];
 	readonly availableTools: readonly AvailableTool[];
+	/**
+	 * Optional streaming callback — called with each token delta as it
+	 * arrives from the LLM. The Runner uses this to show live progress
+	 * during the "calling-llm" phase. Only effective when the backend
+	 * supports streaming (mana-server / cloud tiers).
+	 */
+	readonly onToken?: (delta: string) => void;
 }
 
 export interface PlannedStep {