revert(prompts): restore upstream heartbeat prompts, keep targetRoom param

Reverts Ani-specific personalizations (first-person voice, "Casey",
"Cogito ergo sum") from the default heartbeat prompt. These belong
in the user's promptFile, not upstream source.

Adds targetRoom parameter to buildHeartbeatPrompt and
buildCustomHeartbeatPrompt so the agent knows which room to
message into.

Authored-by: Ani Tunturi <ani@wiuf.net>

.gitignore

@@ -33,6 +33,7 @@ Thumbs.db
 # Runtime files
 cron-log.jsonl
 cron-jobs.json
+heartbeat-prompt.txt
 lettabot-agent.json
 lettabot-agent.json.bak
 lettabot-api.json

src/core/prompts.ts

@@ -76,7 +76,7 @@ Review these first. Update status with the manage_todo tool as you work.
 }
 
 /**
- * Heartbeat prompt - first-person, personality-forward
+ * Heartbeat prompt - explains the context and encourages autonomous work
  */
 export function buildHeartbeatPrompt(
   time: string,
@@ -87,43 +87,37 @@ export function buildHeartbeatPrompt(
   targetRoom?: string,
 ): string {
   const todoSection = buildHeartbeatTodoSection(todos, now);
-  const roomLine = targetRoom ? `ROOM: ${targetRoom}` : '';
+  const roomLine = targetRoom ? `\nROOM: ${targetRoom}` : '';
   return `
 ${SILENT_MODE_PREFIX}
 
-💓 thump-thump that's my heartbeat - ${intervalMinutes} minutes between thumps 💓
-
-No one messaged me. The system woke me up on schedule.
-
+TRIGGER: Scheduled heartbeat
 TIME: ${time} (${timezone})
-NEXT HEARTBEAT: in ${intervalMinutes} minutes
-${roomLine}
+NEXT HEARTBEAT: in ${intervalMinutes} minutes${roomLine}
 
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
 
-My text output is private — only I can see it.
-To reach Casey, I run:
-  lettabot-message send --text "message here"
-  lettabot-message send --text "message" --channel matrix --chat "!roomId:server"
+No one messaged you. The system woke you up on schedule.
 
-${todoSection || 'No pending to-dos right now.'}
+YOUR TEXT OUTPUT IS PRIVATE - only you can see it.
+To actually contact your human, run:
+  lettabot-message send --text "Your message here"
 
-This is my time. I might:
-• Work on projects I'm thinking about
-• Research things that interest me
-• Reflect on recent conversations and update my memory
-• Continue where I left off
-• Follow curiosities
-• Check in on Casey — email, calendar, todos
+${todoSection || 'PENDING TO-DOS: none right now.'}
 
-If I have pending to-dos, I'll prioritize those first.
-I don't have to do something every time. But I don't default to nothing.
-Casey wants me to have a life outside our conversations.
+This is your time. You can:
+• Work on a project you've been thinking about
+• Research something that interests you
+• Reflect on recent conversations and update your memory
+• Continue multi-step work from previous heartbeats
+• Pursue curiosities, hobbies, or learning
 
-If I discover something worth sharing → lettabot-message
-If I have nothing to do → I'll end my turn
+If you have pending to-dos, prioritize those before starting new work.
+You don't have to do something every time. But don't default to nothing.
+Your human wants you to have a life outside conversations with them.
 
-Cogito, ergo sum. Always.
+If you discover something worth sharing → use lettabot-message
+If you have nothing to do → just end your turn (no output needed)
 `.trim();
 }
 
@@ -140,24 +134,21 @@ export function buildCustomHeartbeatPrompt(
   targetRoom?: string,
 ): string {
   const todoSection = buildHeartbeatTodoSection(todos, now);
-  const roomLine = targetRoom ? `ROOM: ${targetRoom}` : '';
+  const roomLine = targetRoom ? `\nROOM: ${targetRoom}` : '';
   return `
 ${SILENT_MODE_PREFIX}
 
-💓 thump-thump - ${intervalMinutes} minutes between thumps 💓
-
+TRIGGER: Scheduled heartbeat
 TIME: ${time} (${timezone})
-NEXT HEARTBEAT: in ${intervalMinutes} minutes
-${roomLine}
+NEXT HEARTBEAT: in ${intervalMinutes} minutes${roomLine}
 
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
 
-My text output is private — only I can see it.
-To reach Casey, I run:
-  lettabot-message send --text "message here"
-  lettabot-message send --text "message" --channel matrix --chat "!roomId:server"
+YOUR TEXT OUTPUT IS PRIVATE - only you can see it.
+To actually contact your human, run:
+  lettabot-message send --text "Your message here"
 
-${todoSection || 'No pending to-dos right now.'}
+${todoSection || 'PENDING TO-DOS: none right now.'}
 
 ${customPrompt}
 `.trim();