fix: issue-triage quick wins (extraction, MCP probes, gitignore, CJK, impact) (#654)

Batch of small, localized fixes from an open-issue triage:

- .codegraph/.gitignore now ignores everything but itself, so the database,
  daemon.pid, sockets, and logs stop showing up in git status (#492, #484)
- MCP server answers resources/list and prompts/list with empty lists instead
  of -32601, clearing scary log lines in opencode/Codex (#621)
- index SAP HANA .xsjs/.xsjslib as JavaScript (#556) and TS .mts/.cts (#366)
- visit anonymous AMD/CommonJS/IIFE wrapper bodies so their inner functions and
  calls are indexed instead of coming up empty (#528)
- batch the changed-file lookup so a huge first sync no longer hits
  "too many SQL variables" (#540)
- list files with `git ls-files -z` so non-ASCII/CJK paths survive
  core.quotepath and are no longer silently skipped (#541)
- attach Go methods on generic receivers (*T[P]) to their type (#583, RC1)
- impact no longer climbs the structural `contains` edge, so a leaf symbol
  stops dragging in its sibling methods (#536)
- README: explicit `codegraph install` step, run in a new shell (#631)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/extraction/tree-sitter.ts

@@ -630,7 +630,19 @@ export class TreeSitterExtractor {
         }
       }
     }
-    if (name === '<anonymous>') return; // Skip anonymous functions
+    if (name === '<anonymous>') {
+      // Don't emit a node for the anonymous wrapper itself, but still visit its
+      // body: AMD/RequireJS and CommonJS module wrappers (`define([], function(){…})`,
+      // `(function(){…})()`) hold named inner functions and calls that would
+      // otherwise be lost — the dispatcher set skipChildren, so nothing else
+      // descends into this subtree. (#528)
+      const body = this.extractor.resolveBody?.(node, this.extractor.bodyField)
+        ?? getChildByField(node, this.extractor.bodyField);
+      if (body) {
+        this.visitFunctionBody(body, '');
+      }
+      return;
+    }
 
     // Check for misparse artifacts (e.g. C++ macros causing "namespace detail" functions)
     // Skip the node but still visit the body for calls and structural nodes