feat: add Zig language support with SCIP indexing

Merge PR #27 from jedisct1 to add comprehensive Zig language support:

Core Changes:
- Add ZigStrategy with complete SCIP-compliant indexing (738 lines)
- Support both Tree-sitter and regex parsing approaches
- Register Zig strategy in SCIPIndexerFactory with priority 95
- Add .zig and .zon file extension support in constants
- Update README.md to document Zig language support

Test Coverage:
- Add complete Zig test project in test/sample-projects/zig/
- Include build.zig, main.zig, root.zig examples
- Cover major Zig language constructs (functions, structs, enums, tests)

Architecture Consistency:
- Maintain clean SCIP strategy architecture
- Remove redundant analyzers system components during merge
- Keep focus on unified SCIP-based indexing approach

This implementation provides full Zig language support following the same
high-quality SCIP standards as other supported languages.

Author: johnhuang316

README.md

@@ -94,7 +94,7 @@ The easiest way to get started with any MCP-compatible application:
 **System & Low-Level:**
 - C/C++ (`.c`, `.cpp`, `.h`, `.hpp`)
 - Rust (`.rs`)
-- Zig (`.zig`)
+- Zig (`.zig`, `.zon`)
 - Go (`.go`)
 
 **Object-Oriented:**

src/code_index_mcp/constants.py

@@ -41,7 +41,7 @@
     '.fs', '.fsx',                    # F#
     '.clj', '.cljs',                  # Clojure
     '.vim',                           # Vim script
-    '.zig',                           # Zig
+    '.zig', '.zon',                   # Zig
 
     # Web and markup
     '.html', '.htm',                  # HTML

src/code_index_mcp/scip/factory.py

@@ -7,6 +7,7 @@
 from .strategies.javascript_strategy import JavaScriptStrategy
 from .strategies.java_strategy import JavaStrategy
 from .strategies.objective_c_strategy import ObjectiveCStrategy
+from .strategies.zig_strategy import ZigStrategy
 from .strategies.fallback_strategy import FallbackStrategy
 from ..constants import SUPPORTED_EXTENSIONS
 
@@ -34,6 +35,7 @@ def _register_all_strategies(self):
             JavaScriptStrategy(priority=95),
             JavaStrategy(priority=95),
             ObjectiveCStrategy(priority=95),
+            ZigStrategy(priority=95),
         ]
 
         for strategy in language_strategies:
@@ -117,6 +119,8 @@ def list_supported_extensions(self) -> Set[str]:
                 supported.update({'.java'})
             elif isinstance(strategy, ObjectiveCStrategy):
                 supported.update({'.m', '.mm'})
+            elif isinstance(strategy, ZigStrategy):
+                supported.update({'.zig', '.zon'})
             elif isinstance(strategy, FallbackStrategy):
                 # Fallback supports everything, but we don't want to list everything here
                 pass