feat: upgrade to V2 APIs, enhance prompt system, and add branch management tools

- Migrated from V1 to V2 ValTown APIs across all tool implementations
- Renamed prompt system to "valley" with configurable path override
- Added comprehensive branch management tools (create, delete, list, merge)
- Enhanced file operations with better error handling and validation
- Expanded vals tools with new V2 API endpoints and features
- Updated configuration interface to support new API structure
- Improved documentation and integration guides

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: PrashamTrivedi

config.ts

@@ -1,6 +1,7 @@
 import {config as dotenvConfig} from "https://deno.land/x/dotenv@v3.2.2/mod.ts"
 import * as path from "jsr:@std/path"
-export function loadConfig() {
+import {getCliAvailability} from "./lib/vtCli.ts"
+export async function loadConfig() {
     dotenvConfig({export: true})
 
     const API_TOKEN = Deno.env.get("VAL_TOWN_API_TOKEN")
@@ -14,12 +15,16 @@ export function loadConfig() {
     const CLI_PATH = Deno.env.get("VAL_TOWN_CLI_PATH") || "vt" // Default to "vt" in PATH
     // Prompt file paths (can be absolute or relative to CWD)
     const VALLEY_PROMPT_PATH = Deno.env.get("VALLEY_PROMPT_PATH")
+    const useCliIfAvailable = PREFER_CLI ?? false
+    const cliAvailable = useCliIfAvailable && await getCliAvailability(CLI_PATH)
+    const defaultPromptPath = `${import.meta.dirname}/prompts/${cliAvailable ? "valley.txt" : "valley_local.txt"}`
+
 
     // Resolve paths relative to the current working directory if they're not absolute
     const resolvedValleyPath = VALLEY_PROMPT_PATH
         ? (path.isAbsolute(VALLEY_PROMPT_PATH)
             ? VALLEY_PROMPT_PATH
-            : `${import.meta.dirname}/valley.txt`)
+            : defaultPromptPath)
         : undefined
     return {
         apiToken: API_TOKEN,
@@ -31,7 +36,7 @@ export function loadConfig() {
         prompts: {
             valleyPath: resolvedValleyPath,
             // Default paths included with the binary
-            defaultValleyPath: `${import.meta.dirname}/valley.txt`
+            defaultValleyPath: defaultPromptPath
         }
     }
 }