refactor: Convert all hooks to HTTP clients (remove all SQL)

Architecture transformation: Hooks → HTTP → Worker → Database

**context-hook.ts** (843 → 104 lines, 88% reduction)
- Remove all database imports and raw SQL queries
- HTTP GET to /api/context/inject
- Returns both formatted (stderr) and unformatted (stdout) context
- Dual output: colored display for users, plain text for model

**user-message-hook.ts** (updated, 113 lines)
- HTTP GET to /api/context/inject with colors=true
- Displays formatted context to users via stderr
- No database dependencies

**save-hook.ts** (418 → 99 lines, 76% reduction)
- Remove all SessionStore database methods
- HTTP POST to /api/sessions/observations
- Worker handles privacy checks and observation creation
- Fire-and-forget pattern with 2s timeout

**summary-hook.ts** (435 → 200 lines, 54% reduction)
- Remove all SessionStore database methods
- Keep local transcript parsing (hook has file access)
- HTTP POST to /api/sessions/summarize
- Worker handles privacy checks and summary generation

**cleanup-hook.ts** (414 → 90 lines, 78% reduction)
- Remove all SessionStore database methods
- HTTP POST to /api/sessions/complete
- Worker handles session completion and DB cleanup
- Non-fatal if worker unavailable

**Benefits:**
- Zero native module dependencies in hooks (Node.js or Bun compatible)
- Hooks can run in any runtime without recompilation
- All database operations centralized in worker service
- Simpler, more maintainable hook code
- Complete separation of concerns: I/O vs business logic

src/hooks/user-message-hook.ts

@@ -6,8 +6,7 @@
  * has been loaded into their session. Uses stderr as the communication channel
  * since it's currently the only way to display messages in Claude Code UI.
  */
-import { execSync } from "child_process";
-import { join } from "path";
+import { join, basename } from "path";
 import { homedir } from "os";
 import { existsSync } from "fs";
 import { getWorkerPort } from "../shared/worker-utils.js";
@@ -20,7 +19,7 @@ if (!existsSync(nodeModulesPath)) {
   // First-time installation - dependencies not yet installed
   console.error(`
 ---
-🎉  Note: This appears under Plugin Hook Error, but it's not an error. That's the only option for 
+🎉  Note: This appears under Plugin Hook Error, but it's not an error. That's the only option for
    user messages in Claude Code UI until a better method is provided.
 ---
 
@@ -41,14 +40,20 @@ This message was not added to your startup context, so you can continue working
 }
 
 try {
-  // Cross-platform path to context-hook.js in the installed plugin
-  const contextHookPath = join(homedir(), '.claude', 'plugins', 'marketplaces', 'thedotmack', 'plugin', 'scripts', 'context-hook.js');
-  const output = execSync(`node "${contextHookPath}" --colors`, {
-    encoding: 'utf8',
-    windowsHide: true
-  });
-
   const port = getWorkerPort();
+  const project = basename(process.cwd());
+
+  // Fetch formatted context directly from worker API
+  const response = await fetch(
+    `http://127.0.0.1:${port}/api/context/inject?project=${encodeURIComponent(project)}&colors=true`,
+    { method: 'GET', signal: AbortSignal.timeout(5000) }
+  );
+
+  if (!response.ok) {
+    throw new Error(`Worker error ${response.status}`);
+  }
+
+  const output = await response.text();
 
   // If it's after Dec 5, 2025 7pm EST, patch this out
   const now = new Date();