security(sprint1): §1.1/1.3/1.4 — WinRM HTTPS/5986, SHA256 pinning infra, IP regex per-octet

§1.4 — Replace loose IP ValidatePattern with per-octet regex in 4 scripts
  (Invoke-CIJob, Invoke-RemoteBuild, Get-BuildArtifacts, Wait-VMReady)

§1.1 — Migrate all WinRM connections from HTTP/5985 to HTTPS/5986
  - Deploy post-install.ps1: remove AllowUnencrypted=true; self-signed cert + HTTPS listener
    already present; firewall rule restricted to 192.168.79.0/24
  - Setup-WinBuild2025.ps1: assert AllowUnencrypted=false
  - Prepare-WinBuild2025.ps1: preflight uses TCP/5986; Test-WSMan -UseSSL -Port 5986;
    New-PSSession -UseSSL -Port 5986; host AllowUnencrypted save/restore removed (not needed for HTTPS)
  - Invoke-RemoteBuild, Get-BuildArtifacts: New-PSSession -UseSSL -Port 5986 -Authentication Basic
  - Wait-VMReady: New-WSManSessionOption + Test-WSMan -Port 5986 -UseSSL
  - Validate-DeployState, Validate-SetupState: Invoke-Command -UseSSL -Port 5986,
    AllowUnencrypted check → false; AllowUnencrypted host-side removed from both
  - Docs: PLAN, README, ARCHITECTURE, BEST-PRACTICES, HOST-SETUP, WINDOWS-TEMPLATE-SETUP,
    LINUX-TEMPLATE-SETUP, TODO updated

§1.3 — SHA256 hash pinning infrastructure
  - Assert-Hash function + $script:Hashes hashtable added to Setup-WinBuild2025.ps1
  - Assert-Hash called after dotnet-install.ps1, python installer, vs_buildtools.exe downloads
  - Hashes initialized to '' (warn-skip); must be filled before next snapshot refresh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PLAN.md

@@ -16,7 +16,7 @@
 - Gitea self-hosted — `http://10.10.20.11:3100`
 - act_runner v1.0.2 — Windows service su host, label `windows-build`
 - Build VMs: subnet VMnet8 NAT — `192.168.79.0/24`
-- WinRM HTTP/5985 (Basic auth, lab-only)
+- WinRM HTTPS/5986 (Basic auth over HTTPS, self-signed cert, SkipCACheck lab-only)
 
 ### Architettura implementata
 1. Gitea Actions enqueue job → act_runner lo prende