Add reproducible build system, native Unraid plugin, and WebUI

- versions.env pins podman, conmon, crun, netavark, aardvark-dns, passt,
  and fuse-overlayfs to verified upstream source checksums; SlackBuild
  recipes, scripts/build-packages.sh, checksums.sh, release.sh, and
  update-versions.sh implement the reproducible pipeline; GitHub Actions
  workflows build in a Slackware container and publish releases without
  committing any binaries.

- plugin/podman.plg installs/updates/removes all eight packages (the
  seven components plus the plugin's own unraid-podman scaffolding
  package) via upgradepkg, using the official Unraid array-event hook
  mechanism (event/disks_mounted, event/stopping) instead of editing
  /boot/config/go. rc.podman and the sbin/ helper scripts implement
  storage creation, config seeding/sync, preflight checks, autostart
  with per-container Safe-Mode, and package verify/update/rollback.

- webui/plugins/podman implements the Dashboard, Containers, Pods,
  Images, Volumes, Networks, Logs, Terminal, Compose, and Settings
  panels against the approved mockup (webui/mockups/prototype.html),
  talking to podman system service exclusively via PodmanClient.php
  (libpod REST API over the Unix socket), with two documented
  exceptions: Terminal's one-shot exec model and Compose's use of the
  podman compose CLI, since libpod has no REST equivalent for either.

- docs/ARCHITECTURE.md and docs/ROADMAP.md record the design decisions
  and honest current status (syntax-checked, unit- and
  integration-tested against fake sockets/servers; not yet run against
  a real Unraid/Podman/Slackware system).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,39 @@
+---
+name: Bug report
+about: Report a problem with the plugin
+title: "[Bug] "
+labels: bug
+assignees: ""
+---
+
+## Description
+
+A clear description of what went wrong.
+
+## Environment
+
+- Unraid version:
+- unraid-podman plugin version:
+- Podman version (`podman version`, if available):
+- Storage backend (Cache pool / Array disk), pool filesystem (XFS/BTRFS/ZFS):
+- Docker also installed/running? (yes/no):
+
+## Steps to reproduce
+
+1. ...
+2. ...
+
+## Expected behavior
+
+## Actual behavior
+
+## Relevant logs
+
+Attach or paste relevant excerpts from:
+- `/mnt/*/system/podman/logs/podman-service.log`
+- Unraid System Log (`Tools -> System Log`)
+- `rc.podman status` output
+
+Please redact any secrets (registry credentials, tokens) before posting.
+
+## Additional context

.github/ISSUE_TEMPLATE/config.yml

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+blank_issues_enabled: false
+contact_links:
+  - name: Security vulnerability
+    url: https://github.com/OWNER/unraid-podman/security/advisories/new
+    about: Please report security issues privately — see SECURITY.md, not a public issue.
+  - name: General discussion / questions
+    url: https://github.com/OWNER/unraid-podman/discussions
+    about: Usage questions and design discussions that aren't a concrete bug or feature request.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,23 @@
+---
+name: Feature request
+about: Suggest an enhancement or new capability
+title: "[Feature] "
+labels: enhancement
+assignees: ""
+---
+
+## Problem
+
+What are you trying to do that isn't currently possible or is unnecessarily hard?
+
+## Proposed solution
+
+## Alternatives considered
+
+## Which architecture phase does this fit?
+
+See [docs/ROADMAP.md](../../docs/ROADMAP.md) — e.g. MVP / WebUI / Rootless /
+Docker-optional / Pods. If unsure, leave blank; this helps triage against the
+existing phased plan rather than scope-creeping the current phase.
+
+## Additional context