fix(observer): use _clv2_resolve_homunculus_dir (matches lib export) (#2511)

Commit 2d40baac (PR #2304) renamed `_ecc_*` -> `_clv2_*` but missed this
single call site. The launcher sources `scripts/lib/homunculus-dir.sh` which
only exports `_clv2_resolve_homunculus_dir`, so any user enabling the
observer (`observer.enabled: true`) gets:

  start-observer.sh: line 40: _ecc_resolve_homunculus_dir: command not found

The hook (`observe.sh`) uses the correct name and writes observations, but
the lazy-start path fails silently via nohup, so the symptom is
"observations grow forever, no new instincts". Confirmed on
affaan-m/ECC@40927950c (HEAD of main).

Default `observer.enabled: false` masks the bug for new users. Opt-in
users hit it on first manual `start-observer.sh start` or first lazy-start
after enabling.

Fix: rename the single call to `_clv2_resolve_homunculus_dir` to match
the lib export and every other caller in the skill.

skills/continuous-learning-v2/agents/start-observer.sh

@@ -37,7 +37,7 @@ PYTHON_CMD="${CLV2_PYTHON_CMD:-}"
 
 # shellcheck disable=SC1091
 . "${SKILL_ROOT}/scripts/lib/homunculus-dir.sh"
-CONFIG_DIR="$(_ecc_resolve_homunculus_dir)"
+CONFIG_DIR="$(_clv2_resolve_homunculus_dir)"
 if [ -n "${CLV2_CONFIG:-}" ]; then
   CONFIG_FILE="$CLV2_CONFIG"
 elif [ -f "${CONFIG_DIR}/config.json" ]; then