fix: remove project filter from file-context hook — cwd != stored project name

The handler was passing input.cwd (full absolute path) as the project
filter, but observations store short project names ('san-diego', not
'/Users/.../san-diego'). This caused zero results for every query.
Removing the filter entirely is better: cross-project observations
about the same file are useful for duplicate prevention.

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

src/cli/handlers/file-context.ts

@@ -104,9 +104,6 @@ export const fileContextHandler: EventHandler = {
     // Query worker for observations related to this file
     try {
       const queryParams = new URLSearchParams({ path: filePath });
-      if (input.cwd) {
-        queryParams.set('project', input.cwd);
-      }
 
       const response = await workerHttpRequest(`/api/observations/by-file?${queryParams.toString()}`, {
         method: 'GET',