[ACTP] PAR: warn on misconfigured rshell allowed_paths entries

[julesmcrt]

What does this PR do?

Adds two advisory warnings at PAR config load that surface common allowed_paths misconfigurations which would otherwise silently fail at task execution:

• Backslash entries: the operator-side allow-list is forward-slash (Linux-form) only; Windows-native paths never match the backend's Linux-style list.
• Non-directory entries: rshell's sandbox is built on os.Root, which only accepts directory handles. File entries get silently dropped at runner creation, producing permission-denied for every open.

Both warnings are advisory — entries still flow through to the handler; the warnings make the silent-failure modes observable in agent logs.

Stacked on top of #49945 (PR1 in the split)

This is PR2 of 4 splitting #49825. Base: PR1 branch. Will retarget to main after PR1 lands.

Describe how you validated your changes

• New pass-through tests in transform_test.go verify that backslash and non-directory entries flow to the handler unchanged (the warnings are side effects).
• All 36 tests in pkg/privateactionrunner/adapters/config pass; linter clean.

🤖 Generated with Claude Code

[datadog-prod-us1-3]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 50.21%

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: da001c9 | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

Files inventory check summary

File checks results against ancestor c1888d89:

Results for datadog-agent_7.80.0~devel.git.264.da001c9.pipeline.109970833-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor c1888d8
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	+4.0 KiB (0.00% increase)	738.997 → 739.001 → 750.310
✅	agent_msi	+6.5 KiB (0.00% increase)	604.157 → 604.163 → 620.770
✅	agent_rpm_amd64	+4.0 KiB (0.00% increase)	738.980 → 738.984 → 750.280
✅	agent_rpm_arm64	+4.0 KiB (0.00% increase)	717.073 → 717.077 → 724.050
✅	agent_suse_amd64	+4.0 KiB (0.00% increase)	738.980 → 738.984 → 750.280
✅	agent_suse_arm64	+4.0 KiB (0.00% increase)	717.073 → 717.077 → 724.050
✅	docker_agent_amd64	+4.0 KiB (0.00% increase)	799.455 → 799.459 → 805.870
✅	docker_agent_arm64	+4.0 KiB (0.00% increase)	802.357 → 802.361 → 809.730
✅	docker_agent_jmx_amd64	+4.0 KiB (0.00% increase)	990.375 → 990.378 → 996.590
✅	docker_agent_jmx_arm64	+4.01 KiB (0.00% increase)	982.055 → 982.059 → 989.410

21 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64_fips	697.423 MiB
✅	agent_heroku_amd64	309.103 MiB
✅	agent_rpm_amd64_fips	697.407 MiB
✅	agent_rpm_arm64_fips	678.532 MiB
✅	agent_suse_amd64_fips	697.407 MiB
✅	agent_suse_arm64_fips	678.532 MiB
✅	docker_cluster_agent_amd64	206.269 MiB
✅	docker_cluster_agent_arm64	220.383 MiB
✅	docker_cws_instrumentation_amd64	7.142 MiB
✅	docker_cws_instrumentation_arm64	6.689 MiB
✅	docker_dogstatsd_amd64	39.347 MiB
✅	docker_dogstatsd_arm64	37.565 MiB
✅	dogstatsd_deb_amd64	30.001 MiB
✅	dogstatsd_deb_arm64	28.142 MiB
✅	dogstatsd_rpm_amd64	30.001 MiB
✅	dogstatsd_suse_amd64	30.001 MiB
✅	iot_agent_deb_amd64	44.372 MiB
✅	iot_agent_deb_arm64	41.361 MiB
✅	iot_agent_deb_armhf	42.097 MiB
✅	iot_agent_rpm_amd64	44.373 MiB
✅	iot_agent_suse_amd64	44.373 MiB

On-wire sizes (compressed)

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	-19.82 KiB (0.01% reduction)	174.984 → 174.965 → 179.160
✅	agent_deb_amd64_fips	+23.39 KiB (0.01% increase)	166.645 → 166.668 → 174.440
✅	agent_heroku_amd64	neutral	74.913 MiB → 80.310
✅	agent_msi	-8.0 KiB (0.01% reduction)	139.270 → 139.262 → 147.550
✅	agent_rpm_amd64	+29.4 KiB (0.02% increase)	176.944 → 176.972 → 182.080
✅	agent_rpm_amd64_fips	+16.8 KiB (0.01% increase)	168.007 → 168.023 → 174.140
✅	agent_rpm_arm64	-3.43 KiB (0.00% reduction)	159.252 → 159.248 → 163.610
✅	agent_rpm_arm64_fips	+8.65 KiB (0.01% increase)	151.449 → 151.457 → 156.850
✅	agent_suse_amd64	+29.4 KiB (0.02% increase)	176.944 → 176.972 → 182.080
✅	agent_suse_amd64_fips	+16.8 KiB (0.01% increase)	168.007 → 168.023 → 174.140
✅	agent_suse_arm64	-3.43 KiB (0.00% reduction)	159.252 → 159.248 → 163.610
✅	agent_suse_arm64_fips	+8.65 KiB (0.01% increase)	151.449 → 151.457 → 156.850
✅	docker_agent_amd64	+21.37 KiB (0.01% increase)	267.115 → 267.136 → 272.990
✅	docker_agent_arm64	+2.45 KiB (0.00% increase)	254.142 → 254.145 → 261.470
✅	docker_agent_jmx_amd64	+16.99 KiB (0.00% increase)	335.778 → 335.795 → 341.610
✅	docker_agent_jmx_arm64	+12.39 KiB (0.00% increase)	318.782 → 318.794 → 326.050
✅	docker_cluster_agent_amd64	+2.97 KiB (0.00% increase)	72.297 → 72.300 → 73.460
✅	docker_cluster_agent_arm64	-2.13 KiB (0.00% reduction)	67.762 → 67.760 → 68.680
✅	docker_cws_instrumentation_amd64	neutral	2.999 MiB → 3.330
✅	docker_cws_instrumentation_arm64	neutral	2.729 MiB → 3.090
✅	docker_dogstatsd_amd64	neutral	15.229 MiB → 15.870
✅	docker_dogstatsd_arm64	neutral	14.549 MiB → 14.890
✅	dogstatsd_deb_amd64	neutral	7.936 MiB → 8.830
✅	dogstatsd_deb_arm64	+2.43 KiB (0.03% increase)	6.818 → 6.820 → 7.750
✅	dogstatsd_rpm_amd64	neutral	7.946 MiB → 8.840
✅	dogstatsd_suse_amd64	neutral	7.946 MiB → 8.840
✅	iot_agent_deb_amd64	-2.2 KiB (0.02% reduction)	11.678 → 11.676 → 13.210
✅	iot_agent_deb_arm64	+2.2 KiB (0.02% increase)	9.981 → 9.983 → 11.620
✅	iot_agent_deb_armhf	neutral	10.186 MiB → 11.780
✅	iot_agent_rpm_amd64	neutral	11.695 MiB → 13.230
✅	iot_agent_suse_amd64	neutral	11.695 MiB → 13.230

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: af292094-2fda-4328-8911-d1c32e4f3be5

Baseline: b15fe93
Comparison: da001c9
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	+4.57	[+1.55, +7.58]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	+4.57	[+1.55, +7.58]	1	Logs
➖	quality_gate_metrics_logs	memory utilization	+1.65	[+1.39, +1.90]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_cumulative	memory utilization	+0.80	[+0.64, +0.96]	1	Logs
➖	ddot_metrics_sum_delta	memory utilization	+0.69	[+0.50, +0.87]	1	Logs
➖	quality_gate_idle	memory utilization	+0.24	[+0.19, +0.29]	1	Logs bounds checks dashboard
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.18	[+0.13, +0.23]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	+0.13	[+0.10, +0.17]	1	Logs bounds checks dashboard
➖	docker_containers_memory	memory utilization	+0.11	[+0.01, +0.21]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.10	[-0.29, +0.49]	1	Logs
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.08	[-0.16, +0.32]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	+0.07	[-0.37, +0.50]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	+0.06	[-0.45, +0.57]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	+0.04	[-0.06, +0.14]	1	Logs
➖	otlp_ingest_metrics	memory utilization	+0.03	[-0.13, +0.19]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.02	[-0.19, +0.24]	1	Logs
➖	file_tree	memory utilization	+0.02	[-0.03, +0.06]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.11, +0.11]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	-0.01	[-0.21, +0.19]	1	Logs
➖	quality_gate_logs	% cpu utilization	-0.12	[-1.09, +0.85]	1	Logs bounds checks dashboard
➖	otlp_ingest_logs	memory utilization	-0.43	[-0.54, -0.32]	1	Logs
➖	ddot_logs	memory utilization	-0.76	[-0.83, -0.69]	1	Logs
➖	ddot_metrics	memory utilization	-0.79	[-0.97, -0.61]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-1.30	[-1.48, -1.12]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	691 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	244.80MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	681 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.16GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.21GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.17GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.18GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	141.00MiB ≤ 147MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	465.97MiB ≤ 495MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	172.55MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	344.83 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	376.01MiB ≤ 430MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.