Rename content_hash/output_hash to cid throughout

Refactor to use IPFS CID as the primary content identifier:
- Update database schema: content_hash -> cid, output_hash -> output_cid
- Update all services, routers, and tasks to use cid terminology
- Update HTML templates to display CID instead of hash
- Update cache_manager parameter names
- Update README documentation

This completes the transition to CID-only content addressing.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tasks/orchestrate_cid.py

@@ -67,7 +67,7 @@ def register_input_cid(
         input_path: Local path to the input file
 
     Returns:
-        Dict with 'cid' and 'content_hash'
+        Dict with 'cid' and 'cid'
     """
     import hashlib
 
@@ -77,7 +77,7 @@ def register_input_cid(
 
     # Compute content hash
     with open(path, "rb") as f:
-        content_hash = hashlib.sha3_256(f.read()).hexdigest()
+        cid = hashlib.sha3_256(f.read()).hexdigest()
 
     # Add to IPFS
     cid = ipfs_client.add_file(path)
@@ -89,7 +89,7 @@ def register_input_cid(
     return {
         "status": "completed",
         "cid": cid,
-        "content_hash": content_hash,
+        "cid": cid,
         "path": str(path),
     }
 
@@ -426,7 +426,7 @@ def run_from_local(
             return {"status": "failed", "phase": "register_input", "input": name, "error": result.get("error")}
 
         input_cids[name] = result["cid"]
-        input_hashes[name] = result["content_hash"]
+        input_hashes[name] = result["cid"]
 
     # Run the pipeline
     return run_recipe_cid.apply_async(