fix(continuous-learning-v2): accept claude-vscode as valid entrypoint (#2134)

The observe.sh Layer 1 entrypoint guard short-circuits with exit 0 when
CLAUDE_CODE_ENTRYPOINT is not in {cli, sdk-ts, claude-desktop}. Claude
Code's VS Code extension sets CLAUDE_CODE_ENTRYPOINT=claude-vscode, so
VS Code users see no observations recorded — observations.jsonl never
gets created and the instinct pipeline stays empty.

Add claude-vscode to the allowlist, mirroring the precedent in #1522
which added claude-desktop the same way.

Add a regression test that spawns observe.sh under bash -x for each
allowed entrypoint (cli, sdk-ts, claude-desktop, claude-vscode) and
each denied entrypoint (unknown-host, claude-cody, mcp), asserting
that allowed entrypoints reach Layer 2's ECC_HOOK_PROFILE check while
denied entrypoints stop at Layer 1.

Fixes #2102

skills/continuous-learning-v2/hooks/observe.sh

@@ -155,7 +155,7 @@ fi
 # Non-interactive SDK automation is still filtered by Layers 2-5 below
 # (ECC_HOOK_PROFILE=minimal, ECC_SKIP_OBSERVE=1, agent_id, path exclusions).
 case "${CLAUDE_CODE_ENTRYPOINT:-cli}" in
-  cli|sdk-ts|claude-desktop) ;;
+  cli|sdk-ts|claude-desktop|claude-vscode) ;;
   *) exit 0 ;;
 esac