fix(telegram): honor TELEGRAM_STATE_DIR/CLAUDE_CONFIG_DIR in skills and server

The server already reads TELEGRAM_STATE_DIR for multi-bot setups, but the
/telegram:access and /telegram:configure skills hardcoded
~/.claude/channels/telegram/ in 11 places. So with a custom state dir the
skill writes access.json to the default location while the server reads
from the override — pairing and allowlist edits silently don't take effect.

Skills now resolve the state dir via shell expansion (TELEGRAM_STATE_DIR →
CLAUDE_CONFIG_DIR/channels/telegram → ~/.claude/channels/telegram) before
any read/write. Server gets the same CLAUDE_CONFIG_DIR fallback. Also adds
Bash(echo)/Bash(chmod) to configure skill's allowed-tools (chmod was already
documented but not allowlisted).

external_plugins/telegram/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "telegram",
   "description": "Telegram channel for Claude Code \u2014 messaging bridge with built-in access control. Manage pairing, allowlists, and policy via /telegram:access.",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "keywords": [
     "telegram",
     "messaging",