feat: add blockchain RPC blocks-range endpoint and marketplace bid listing

Blockchain Node:
- Replace /blocks (pagination) with /blocks-range (height range query)
- Add start/end height parameters with 1000-block max range validation
- Return blocks in ascending height order instead of descending
- Update metrics names (rpc_get_blocks_range_*)
- Remove total count from response (return start/end/count instead)

Coordinator API:
- Add effective_url property to DatabaseConfig (SQLite/PostgreSQL defaults

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

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import httpx
 from collections import defaultdict, deque
 from datetime import datetime
 from typing import Optional
@@ -38,25 +39,51 @@ class ExplorerService:
         self.session = session
 
     def list_blocks(self, *, limit: int = 20, offset: int = 0) -> BlockListResponse:
-        statement = select(Job).order_by(Job.requested_at.desc())
-        jobs = self.session.exec(statement.offset(offset).limit(limit)).all()
+        # Fetch real blockchain data from RPC API
+        try:
+            # Use the blockchain RPC API running on localhost:8082
+            with httpx.Client(timeout=10.0) as client:
+                response = client.get("http://localhost:8082/rpc/blocks", params={"limit": limit, "offset": offset})
+                response.raise_for_status()
+                rpc_data = response.json()
+                
+                items: list[BlockSummary] = []
+                for block in rpc_data.get("blocks", []):
+                    items.append(
+                        BlockSummary(
+                            height=block["height"],
+                            hash=block["hash"],
+                            timestamp=datetime.fromisoformat(block["timestamp"]),
+                            txCount=block["tx_count"],
+                            proposer=block["proposer"],
+                        )
+                    )
+                
+                next_offset: Optional[int] = offset + len(items) if len(items) == limit else None
+                return BlockListResponse(items=items, next_offset=next_offset)
+                
+        except Exception as e:
+            # Fallback to fake data if RPC is unavailable
+            print(f"Warning: Failed to fetch blocks from RPC: {e}, falling back to fake data")
+            statement = select(Job).order_by(Job.requested_at.desc())
+            jobs = self.session.exec(statement.offset(offset).limit(limit)).all()
 
-        items: list[BlockSummary] = []
-        for index, job in enumerate(jobs):
-            height = _DEFAULT_HEIGHT_BASE + offset + index
-            proposer = job.assigned_miner_id or "unassigned"
-            items.append(
-                BlockSummary(
-                    height=height,
-                    hash=job.id,
-                    timestamp=job.requested_at,
-                    txCount=1,
-                    proposer=proposer,
+            items: list[BlockSummary] = []
+            for index, job in enumerate(jobs):
+                height = _DEFAULT_HEIGHT_BASE + offset + index
+                proposer = job.assigned_miner_id or "unassigned"
+                items.append(
+                    BlockSummary(
+                        height=height,
+                        hash=job.id,
+                        timestamp=job.requested_at,
+                        txCount=1,
+                        proposer=proposer,
+                    )
                 )
-            )
 
-        next_offset: Optional[int] = offset + len(items) if len(items) == limit else None
-        return BlockListResponse(items=items, next_offset=next_offset)
+            next_offset: Optional[int] = offset + len(items) if len(items) == limit else None
+            return BlockListResponse(items=items, next_offset=next_offset)
 
     def list_transactions(self, *, limit: int = 50, offset: int = 0) -> TransactionListResponse:
         statement = (

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

@@ -10,6 +10,7 @@ from ..schemas import (
     MarketplaceBidRequest,
     MarketplaceOfferView,
     MarketplaceStatsView,
+    MarketplaceBidView,
 )
 
 
@@ -70,6 +71,47 @@ class MarketplaceService:
         self.session.refresh(bid)
         return bid
 
+    def list_bids(
+        self,
+        *,
+        status: Optional[str] = None,
+        provider: Optional[str] = None,
+        limit: int = 100,
+        offset: int = 0,
+    ) -> list[MarketplaceBidView]:
+        stmt = select(MarketplaceBid).order_by(MarketplaceBid.submitted_at.desc())
+
+        if status is not None:
+            normalised = status.strip().lower()
+            if normalised not in ("pending", "accepted", "rejected"):
+                raise ValueError(f"invalid status: {status}")
+            stmt = stmt.where(MarketplaceBid.status == normalised)
+
+        if provider is not None:
+            stmt = stmt.where(MarketplaceBid.provider == provider)
+
+        stmt = stmt.offset(offset).limit(limit)
+        bids = self.session.exec(stmt).all()
+        return [self._to_bid_view(bid) for bid in bids]
+
+    def get_bid(self, bid_id: str) -> Optional[MarketplaceBidView]:
+        bid = self.session.get(MarketplaceBid, bid_id)
+        if bid:
+            return self._to_bid_view(bid)
+        return None
+
+    @staticmethod
+    def _to_bid_view(bid: MarketplaceBid) -> MarketplaceBidView:
+        return MarketplaceBidView(
+            id=bid.id,
+            provider=bid.provider,
+            capacity=bid.capacity,
+            price=bid.price,
+            notes=bid.notes,
+            status=bid.status,
+            submitted_at=bid.submitted_at,
+        )
+
     @staticmethod
     def _to_offer_view(offer: MarketplaceOffer) -> MarketplaceOfferView:
         status_val = offer.status.value if hasattr(offer.status, "value") else offer.status