Extract all magic numbers into share.config

Unified config file with [server] (user-facing: port, dir, ttl, lang,
etc.) and [internal] (constants: timeouts, buffer sizes, cert params,
UI timings). Replaces both DEFAULTS dict and hardcoded constants.
JS constants (toast_ms, progress_hide_ms) passed through CFG injection.
Old share.conf no longer used.

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

share.config

@@ -0,0 +1,19 @@
+[server]
+port = 3001
+dir = ~/Downloads/shared
+ttl = 7
+san =
+lang = ru
+refresh = 5
+per_page = 10,25,50,100
+
+[internal]
+secs_per_day = 86400
+cleanup_interval = 3600
+ssl_handshake_timeout = 5
+sniff_size = 8192
+chunk_size = 65536
+cert_days = 3650
+cert_key_bits = 2048
+toast_ms = 2500
+progress_hide_ms = 1200