feat: add miner management endpoints and standardize all API paths to /api/v1 prefix

- Add POST /api/v1/miners/{miner_id}/jobs endpoint for listing miner-assigned jobs with filtering
- Add POST /api/v1/miners/{miner_id}/earnings endpoint for miner earnings tracking (mock implementation)
- Add PUT /api/v1/miners/{miner_id}/capabilities endpoint for updating miner capabilities
- Add DELETE /api/v1/miners/{miner_id} endpoint for miner deregistration (sets OFFLINE status)
- Add JobService.fail_job()

apps/coordinator-api/src/app/services/jobs.py

@@ -72,6 +72,17 @@ class JobService:
         
         return self.session.execute(query).scalars().all()
 
+    def fail_job(self, job_id: str, miner_id: str, error_message: str) -> Job:
+        """Mark a job as failed"""
+        job = self.get_job(job_id)
+        job.state = JobState.FAILED
+        job.error = error_message
+        job.assigned_miner_id = miner_id
+        self.session.add(job)
+        self.session.commit()
+        self.session.refresh(job)
+        return job
+
     def cancel_job(self, job: Job) -> Job:
         if job.state not in {JobState.queued, JobState.running}:
             return job

apps/coordinator-api/src/app/services/miners.py

@@ -116,3 +116,15 @@ class MinerService:
     def online_count(self) -> int:
         result = self.session.execute(select(Miner).where(Miner.status == "ONLINE"))
         return len(result.all())
+
+    def deregister(self, miner_id: str) -> None:
+        """Deregister a miner from the system"""
+        miner = self.session.get(Miner, miner_id)
+        if miner is None:
+            raise KeyError("miner not registered")
+        
+        # Set status to OFFLINE instead of deleting to maintain history
+        miner.status = "OFFLINE"
+        miner.session_token = None
+        self.session.add(miner)
+        self.session.commit()