feat: add Micronaut framework route extraction

[lw-yang]

Summary

Adds a new micronautResolver framework resolver that extracts HTTP route nodes from Micronaut annotations, enabling codegraph_explore to resolve URL paths (e.g. /api/v1/executions/search) directly to their handler methods.

Supported annotations:

• Class-level: @Controller("/prefix"), @Client("/prefix")
• Method-level: @Get, @Post, @Put, @Delete, @Patch, @Head, @Options, @Trace, @HttpMethodMapping
• Path syntax: @Get("/path"), @Get(uri = "/path"), @Get(value = "/path"), bare @Get

What it does:

• Detects Micronaut projects via pom.xml / build.gradle / annotation scanning
• Emits kind: 'route' nodes with full resolved paths (class prefix + method path)
• Creates references edges linking route nodes to handler method names
• Supports both Java and Kotlin source files
• Handles interface methods (e.g. @Client declarative HTTP clients) without access modifiers

Files changed

• src/resolution/frameworks/micronaut.ts — New resolver (extract + detect + resolve)
• src/resolution/frameworks/index.ts — Register micronautResolver in the framework list
• __tests__/micronaut.test.ts — 16 test cases covering all annotation patterns

Test plan

• All 16 new Micronaut tests pass
• Existing framework tests (129 tests) pass with no regression
• Manual verification with Kestra codebase (Micronaut project)

Verification on Kestra (real-world Micronaut project)

Ran codegraph init on Kestra (2,877 files) with this branch:

• 399 route nodes extracted from Micronaut controllers
• Route-to-handler edges correctly established, e.g.:

route: GET /api/v1/{tenant}/executions/search
  → file: ExecutionController.java:204
  → handler: searchExecutions (method)
  → edge: references

Sample indexed routes:

GET /api/v1/{tenant}/executions/search           → ExecutionController.java:204
DELETE /api/v1/{tenant}/flows/{namespace}/{id}    → FlowController.java:564
DELETE /api/v1/{tenant}/dashboards/{id}           → DashboardController.java:192
POST /api/v1/{tenant}/executions/{id}/restart    → ExecutionController.java

Before this change, querying /executions/search via CodeGraph returned irrelevant FTS5 matches on the word "search" across unrelated symbols. After this change, the route resolves directly to the handler method with full call-chain traversal.

Closes #971