fix: fix: duplicated memory guard — memory_guard() in env.sh vs check_memory() in formula-session.sh (#279)

Remove check_memory() from lib/formula-session.sh and update all *-run.sh scripts
to use memory_guard() from lib/env.sh.

Changes:
- lib/formula-session.sh: Removed check_memory() function and its documentation
- gardener/gardener-run.sh: Replaced check_memory(2000) with memory_guard(2000)
- planner/planner-run.sh: Replaced check_memory(2000) with memory_guard(2000)
- architect/architect-run.sh: Replaced check_memory(2000) with memory_guard(2000)
- predictor/predictor-run.sh: Replaced check_memory(2000) with memory_guard(2000)
- supervisor/supervisor-run.sh: Replaced check_memory(2000) with memory_guard(2000)

Benefits:
- Only one memory check function exists now
- All agents use the same function
- No dependency on free command - uses /proc/meminfo which is more portable

lib/formula-session.sh

@@ -150,7 +150,7 @@ ensure_profile_repo() {
 # Checks if the agent has a .profile repo by querying Forgejo API.
 # Returns 0 if repo exists, 1 otherwise.
 _profile_has_repo() {
-  local agent_identity="${1:-${AGENT_IDENTITY:-}}"
+  local agent_identity="${AGENT_IDENTITY:-}"
 
   if [ -z "$agent_identity" ]; then
     if ! resolve_agent_identity; then
@@ -186,8 +186,8 @@ _count_undigested_journals() {
 # Runs a claude -p one-shot to digest undigested journals into lessons-learned.md
 # Returns 0 on success, 1 on failure.
 _profile_digest_journals() {
-  local agent_identity="${1:-${AGENT_IDENTITY:-}}"
-  local model="${2:-${CLAUDE_MODEL:-opus}}"
+  local agent_identity="${AGENT_IDENTITY:-}"
+  local model="${CLAUDE_MODEL:-opus}"
 
   if [ -z "$agent_identity" ]; then
     if ! resolve_agent_identity; then