docs: update COMMANDS.md and EXAMPLES.md for new apm and fleet commands

Add apm troubleshooting list to command index, and usage examples for
apm troubleshooting list and fleet agents list --filter.

Author: knusbaum

docs/COMMANDS.md

@@ -50,7 +50,7 @@ pup <domain> <subgroup> <action> [options] # Nested commands
 | error-tracking | issues (search, get) | src/commands/error_tracking.rs | ✅ |
 | scorecards | list, get | src/commands/scorecards.rs | ✅ |
 | usage | summary, hourly | src/commands/usage.rs | ✅ |
-| apm | services (list, stats, operations, resources), entities (list), dependencies (list), flow-map | src/commands/apm.rs | ✅ |
+| apm | services (list, stats, operations, resources), entities (list), dependencies (list), flow-map, troubleshooting (list) | src/commands/apm.rs | ✅ |
 | cost | projected, attribution, by-org, aws-config (list, get, create, delete), azure-config (list, get, create, delete), gcp-config (list, get, create, delete) | src/commands/cost.rs | ✅ |
 | product-analytics | events send | src/commands/product_analytics.rs | ✅ |
 | data-governance | scanner-rules (list) | src/commands/data_governance.rs | ✅ |

docs/EXAMPLES.md

@@ -285,6 +285,17 @@ pup security findings search \
   --query="@severity:high"
 ```
 
+## APM Troubleshooting
+
+### List Instrumentation Errors for a Host
+```bash
+# Show APM instrumentation errors for a specific host
+pup apm troubleshooting list --hostname my-host
+
+# Narrow results to a specific time window
+pup apm troubleshooting list --hostname my-host --timeframe 4h
+```
+
 ## Infrastructure
 
 ### List Hosts
@@ -296,6 +307,20 @@ pup infrastructure hosts list
 pup infrastructure hosts list --filter="env:production"
 ```
 
+## Fleet
+
+### List Fleet Agents
+```bash
+# Filter agents by hostname
+pup fleet agents list --filter "hostname:my-host"
+
+# Filter by IP address
+pup fleet agents list --filter "ip_address:1.2.3.4"
+
+# Boolean filter expression
+pup fleet agents list --filter "(hostname:host-a OR hostname:host-b) AND env:prod"
+```
+
 ### Get Host
 ```bash
 pup infrastructure hosts get "host-name"