fix: Migrate review-pr.sh to SDK + pr-lifecycle (#800)

Move SID_FILE recovery into agent_recover_session() in lib/agent-sdk.sh
to eliminate remaining duplicate block between dev-agent.sh and
review-pr.sh.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

dev/dev-agent.sh

@@ -243,10 +243,7 @@ if [ -n "$PR_NUMBER" ]; then
 fi
 
 # Recover session_id from .sid file (crash recovery)
-if [ -f "$SID_FILE" ]; then
+agent_recover_session
-  _AGENT_SESSION_ID=$(cat "$SID_FILE")
-  log "recovered session_id: ${_AGENT_SESSION_ID:0:12}..."
-fi
 
 # =============================================================================
 # WORKTREE SETUP

lib/agent-sdk.sh

@@ -12,13 +12,21 @@
 #   agent_run [--resume SESSION_ID] [--worktree DIR] PROMPT
 #
 # After each call, _AGENT_SESSION_ID holds the session ID (also saved to SID_FILE).
-# Recover a previous session on startup:
+# Call agent_recover_session() on startup to restore a previous session.
-#   if [ -f "$SID_FILE" ]; then _AGENT_SESSION_ID=$(cat "$SID_FILE"); fi
 
 set -euo pipefail
 
 _AGENT_SESSION_ID=""
 
+# agent_recover_session — restore session_id from SID_FILE if it exists.
+# Call this before agent_run --resume to enable session continuity.
+agent_recover_session() {
+  if [ -f "$SID_FILE" ]; then
+    _AGENT_SESSION_ID=$(cat "$SID_FILE")
+    log "agent_recover_session: ${_AGENT_SESSION_ID:0:12}..."
+  fi
+}
+
 # agent_run — synchronous Claude invocation (one-shot claude -p)
 # Usage: agent_run [--resume SESSION_ID] [--worktree DIR] PROMPT
 # Sets: _AGENT_SESSION_ID (updated each call, persisted to SID_FILE)

review/review-pr.sh

@@ -135,10 +135,7 @@ if [ -n "$PREV_REV" ] && [ "$PREV_REV" != "null" ]; then
 fi
 
 # Recover session_id from .sid file (re-review continuity)
-if [ -f "$SID_FILE" ]; then
+agent_recover_session
-  _AGENT_SESSION_ID=$(cat "$SID_FILE")
-  log "recovered session_id: ${_AGENT_SESSION_ID:0:12}..."
-fi
 
 # =============================================================================
 # FETCH DIFF