refactor(skills): convert absolute paths to workspace-relative + relocate agent-sessions.yaml to .hermes/

Changes:
- skills/lib.sh: AGENT_SESSIONS_YAML default moved from ~/PuKi/lab/.../agent-sessions.yaml
  to <workspace_root>/.hermes/agent-sessions.yaml (relative via BASH_SOURCE)
- 6 SKILL.md: descriptions + 'Single source of truth' lines updated to .hermes/agent-sessions.yaml
- 6 SKILL.md: bash examples (~/PuKi/lab/agent_sessions/skills/...) → relative paths
- SKILL.md file:// links converted from absolute to relative (resolves workspace tool warnings)
- tmux-agent-orchestrate-create/SKILL.md: removed outdated wrapper template reference
- lib.sh internal comments: removed /home/godopu16/PuKi/lab example
- All scripts: internal source/path references use relative resolution

Verified on isolated server -L agy-relative-path-test (kill-server after):
- syntax check PASS
- E2E: create_session.sh auto-creates .hermes/agent-sessions.yaml at new location
- status.sh reads new location correctly
- 0 leftover absolute path references
- Global skill non-interference verified
- Main isolated server -L multi-agent-canary untouched

skills/tmux-agent-orchestrate-create/scripts/create_session.sh

@@ -171,8 +171,8 @@ if [ -n "$SUBMIT_JOB_PROMPT" ]; then
 fi
 
 if [ ! -f "$AGENT_SESSIONS_YAML" ]; then
-  echo "ERROR: $AGENT_SESSIONS_YAML not found. Run init first." >&2
-  exit 4
+  mkdir -p "$(dirname "$AGENT_SESSIONS_YAML")"
+  echo "tmux_sessions: []" > "$AGENT_SESSIONS_YAML"
 fi
 
 # atomic_dump_yaml: flock + temp+rename + .bak + schema validate (P0-B).