feat(planning): full chat history + auto-advance phases

Three fixes that together restore the planning UX:

- Dashboard reopen showed only a 500-char truncated excerpt of the last
  assistant message. Backend now reads the Claude session JSONL directly
  and returns full per-turn history; frontend iterates and renders all
  bubbles, falling back to last_text_excerpt when the JSONL is missing.
- Phases never advanced because the agent ran /plan-* skills inline as
  tool calls and the marker protocol was loose. Tightened the planning
  prompt (mandatory PHASE_STATUS marker on the last line of every turn,
  ban on inline phase invocation), and the frontend now auto-calls
  /plan/advance when phase_ready=true.
- The phase strip never showed visual state because data-phase values
  ("office-hours") didn't match orchestrator phase names ("/office-hours").
  Added normalizePhase + cleanup of PHASE_STATUS markers from rendered
  bubbles.

Also bumps eco.py session-content truncation from 2k to 20k so /eco
session views aren't cut mid-response either.

Bumps last_text_excerpt fallback in planning_session.py from 500 to
50_000 so even when the JSONL is unavailable, the bubble isn't sliced
mid-word.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

dashboard/handlers/eco.py

@@ -155,7 +155,7 @@ class EcoHandlers:
                     if isinstance(content, str):
                         text = content.replace('[EXTERNAL CONTENT]\n', '').replace('\n[END EXTERNAL CONTENT]', '').strip()
                         if text:
-                            messages.append({'role': 'user', 'text': text[:2000]})
+                            messages.append({'role': 'user', 'text': text[:20000]})
                 elif t == 'assistant':
                     msg = d.get('message', {})
                     content = msg.get('content', '')
@@ -163,9 +163,9 @@ class EcoHandlers:
                         parts = [block['text'] for block in content if block.get('type') == 'text']
                         text = '\n'.join(parts).strip()
                         if text:
-                            messages.append({'role': 'assistant', 'text': text[:2000]})
+                            messages.append({'role': 'assistant', 'text': text[:20000]})
                     elif isinstance(content, str) and content.strip():
-                        messages.append({'role': 'assistant', 'text': content[:2000]})
+                        messages.append({'role': 'assistant', 'text': content[:20000]})
 
             self.send_json({'messages': messages})
         except Exception as e: