feat: add YAML configuration support

docs/server.example.yaml

@@ -0,0 +1,64 @@
+# olcrtc server config example
+# Run with: olcrtc -config server.yaml
+# Any CLI flag (e.g. -key, -id) overrides the corresponding YAML field.
+
+mode: srv
+
+# Connection topology
+link: direct           # p2p link type
+carrier: ""            # leave empty for default selection from auth provider
+
+auth:
+  provider: wbstream   # telemost | jazz | wbstream | none
+
+room:
+  id: "ROOM_ID_HERE"
+  client_id: "default" # deprecated: server identifier (will be removed in upcoming refactor)
+
+crypto:
+  # 32-byte hex (64 chars). Generate with: openssl rand -hex 32
+  key: "REPLACE_ME_WITH_64_HEX_CHARS"
+
+net:
+  transport: datachannel   # datachannel | videochannel | seichannel | vp8channel
+  dns: "8.8.8.8:53"
+
+# Outbound SOCKS5 proxy for server-side egress (optional)
+socks:
+  proxy_addr: ""           # e.g. "127.0.0.1"
+  proxy_port: 0            # e.g. 1080
+
+# Direct engine mode — only used when auth.provider is "none"
+engine:
+  name: ""    # livekit | goolom | salutejazz
+  url: ""
+  token: ""
+
+# vp8channel tuning (only when net.transport == vp8channel)
+vp8:
+  fps: 25
+  batch_size: 1
+
+# seichannel tuning (only when net.transport == seichannel)
+sei:
+  fps: 20
+  batch_size: 1
+  fragment_size: 900
+  ack_timeout_ms: 3000
+
+# videochannel tuning (only when net.transport == videochannel)
+video:
+  width: 1920
+  height: 1080
+  fps: 30
+  bitrate: "2M"
+  hw: none           # none | nvenc
+  codec: qrcode      # qrcode | tile (tile requires 1080x1080)
+  qr_size: 0         # 0 = auto
+  qr_recovery: low   # low (7%) | medium (15%) | high (25%) | highest (30%)
+  tile_module: 4     # 1..270, only for codec: tile
+  tile_rs: 20        # 0..200, only for codec: tile
+
+data: data           # data directory (names files etc.)
+debug: false
+ffmpeg: ffmpeg       # path to ffmpeg binary (only used by videochannel)