feat: complete the Info API area (10 new functions)

[mikemadeja]

Summary

Implements the remaining "FTL information" endpoints, closing 10 of the original 54 missing API operations - the largest single-category gap after this PR is Domains (8) and Clients (7).

• Get-PiHoleInfoClient (/info/client) - info about the requesting client
• Get-PiHoleInfoLogin (/info/login) - login page info
• Get-PiHoleInfoSystem (/info/system) - uptime, memory, CPU
• Get-PiHoleInfoFtl (/info/ftl) - gravity/group/list counts, dnsmasq metrics
• Get-PiHoleInfoSensors (/info/sensors) - temperature sensors
• Get-PiHoleInfoDatabase (/info/database) - long-term DB file/query stats
• Get-PiHoleInfoVersion (/info/version) - Core/Web/FTL/Docker versions
• Get-PiHoleInfoMetrics (/info/metrics) - live DNS/DHCP metrics
• Get-PiHoleInfoMessageCount (/info/messages/count)
• Remove-PiHoleInfoMessage (/info/messages/{id}) - supports comma-separated multiple IDs per the API

Design note: Get-PiHoleInfoClient and Get-PiHoleInfoLogin intentionally have no -Password parameter and never call Request-PiHoleAuth. The live API spec marks both with security: [], and this was confirmed against the real server (both work with zero auth headers) - makes sense given their purpose, since login-page info has to be available before you're logged in.

Also fixed while in the area: Get-PiHoleInfoDatabase's earliest_timestamp/earliest_timestamp_disk return $null (not epoch 1970) when the API sends 0, since the spec documents 0.0 as "no queries stored yet" - same zero-guard pattern already used for Get-PiHoleList's DateUpdated. And Get-PiHoleInfoMessage had the same stray break bug fixed elsewhere in the module, plus was missing a real .DESCRIPTION/.EXAMPLE.

Test plan

• Invoke-ScriptAnalyzer -Path .\PiHoleShell -Recurse - clean
• Verified all 10 new functions against a real Pi-hole v6 server: formatted output, -RawOutput, and (where applicable) bad-password/not-found error handling
• New integration test files for all 10 functions - 33 tests total across the FTLInformation folder, all passing
• Full non-integration suite passes with no regressions (143 tests)
• Regenerated README.md

🤖 Generated with Claude Code