init: project structure, .gitignore, .env.example, runners.conf.example

- .gitignore: excludes .env, runners.conf, certs, temp files, editor files
- .env.example: all configuration variables with sections and descriptions
- runners.conf.example: dynamic runner definition format (pipe-delimited)
- PLAN.md: comprehensive implementation plan with DoD for all 18 milestones
- CLAUDE.md: project conventions and instructions

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

runners.conf.example

@@ -0,0 +1,20 @@
+# =============================================================================
+# runners.conf — Gitea Actions Runner Definitions
+# Copy to runners.conf and edit. One runner per line.
+# Use manage_runner.sh to add/remove runners dynamically.
+# =============================================================================
+#
+# FORMAT: name|ssh_host|ssh_user|ssh_port|data_path|labels|type
+#
+#   name       — Display name in Gitea admin panel
+#   ssh_host   — IP address or hostname (for local machine, use "local")
+#   ssh_user   — SSH username (ignored if ssh_host is "local")
+#   ssh_port   — SSH port (ignored if ssh_host is "local")
+#   data_path  — Absolute path for runner binary + data on that machine
+#   labels     — Comma-separated runner labels (used in workflow runs-on)
+#   type       — "docker" (Linux, runs jobs in containers) or "native" (macOS, runs jobs on host)
+#
+# EXAMPLES:
+unraid-runner|192.168.1.10|root|22|/mnt/nvme/gitea-runner|linux|docker
+fedora-runner|192.168.1.20|user|22|/mnt/nvme/gitea-runner|linux|docker
+macbook-runner|local|_|_|~/gitea-runner|macos|native