fix(logging): keep the reason on passive suspicious logs and document dynamic rules

[rennf93]

Closes #164

• Passive suspicious lines without a trigger now read [PASSIVE MODE] Suspicious activity detected from <ip>: ... - Reason: <reason> - Headers: ... instead of the penetration wording with the reason dropped. Lines with a trigger are unchanged.
• enable_dynamic_rules (field description, docs/configuration/security-config.md and the agent skill reference) now lists what a rule changes: it bans the IPs in ip_blacklist for ip_ban_duration, unbans ip_whitelist, adds suspicious_patterns, and replaces blocked_countries, whitelist_countries, the rate limits, block_cloud_providers, blocked_user_agents, the feature toggles, the auto-ban settings and emergency mode. I checked the list against every config write in guard_core/handlers/_dynamic_rule_application.py.

Gate: 21570 passed, 100% coverage on e9a2c54; the docs-only follow-up 91c2cef ran the config and docs subset (1713 passed), CI runs the full suite. CI may hit the master timing flakes that #163 fixes.

[github-actions]

Detection gate report

All detection gate shards passed.

Shard arbiter-grammar

Gate green: no category regressed against its committed baseline and no benign string is newly flagged.

Total recall: n/a. Total false-positive rate: n/a.
Documented known gaps: 0. Documented known false positives: 0. Both stay in the denominators.

Full per-case output is in the job log.

Shard benchmarks-and-rest

Gate green: no category regressed against its committed baseline and no benign string is newly flagged.

Total recall: 378/386 (97.9%). Total false-positive rate: 23/370 (6.2%).
Documented known gaps: 8. Documented known false positives: 23. Both stay in the denominators.

Category	Recall	False positives
cmd_injection	38/46 (82.6%)	10/370 (2.7%)
cms_probing	36/36 (100.0%)	0/370 (0.0%)
code_injection	3/3 (100.0%)	0/370 (0.0%)
deserialization	18/18 (100.0%)	0/370 (0.0%)
dir_traversal	10/10 (100.0%)	0/370 (0.0%)
file_inclusion	16/16 (100.0%)	3/370 (0.8%)
file_upload	32/32 (100.0%)	0/370 (0.0%)
http_split	4/4 (100.0%)	0/370 (0.0%)
ldap	25/25 (100.0%)	0/370 (0.0%)
nosql	10/10 (100.0%)	0/370 (0.0%)
path_traversal	13/13 (100.0%)	0/370 (0.0%)
proto_pollution	8/8 (100.0%)	0/370 (0.0%)
recon	23/23 (100.0%)	0/370 (0.0%)
sensitive_file	16/16 (100.0%)	0/370 (0.0%)
sqli	38/38 (100.0%)	6/370 (1.6%)
ssrf	32/32 (100.0%)	4/370 (1.1%)
template	13/13 (100.0%)	1/370 (0.3%)
xml	4/4 (100.0%)	0/370 (0.0%)
xss	39/39 (100.0%)	0/370 (0.0%)

Full per-case output is in the job log.

Shard builtin-safety

Gate green: no category regressed against its committed baseline and no benign string is newly flagged.

Total recall: n/a. Total false-positive rate: n/a.
Documented known gaps: 0. Documented known false positives: 0. Both stay in the denominators.

Full per-case output is in the job log.

Shard cpu-load-builtin-safety

Gate green: no category regressed against its committed baseline and no benign string is newly flagged.

Total recall: n/a. Total false-positive rate: n/a.
Documented known gaps: 0. Documented known false positives: 0. Both stay in the denominators.

Full per-case output is in the job log.

Shard hardening-canaries

Gate green: no category regressed against its committed baseline and no benign string is newly flagged.

Total recall: n/a. Total false-positive rate: n/a.
Documented known gaps: 0. Documented known false positives: 0. Both stay in the denominators.

Full per-case output is in the job log.