feat(frameworks): CodeIgniter 3 support

[darkspock]

Adds a CodeIgniter 3 framework resolver alongside Laravel. Same shape as the existing PHP support — FrameworkResolver in src/resolution/frameworks/codeigniter.ts, one line in the registry, parameterized tests in the existing framework test file.

What it captures

1. Explicit routes from application/config/routes.php:

• $route['pattern'] = 'controller/method'
• HTTP-verb-scoped: $route['x']['POST'] = '...'
• CI3 wildcards preserved: (:any), (:num)
• Reserved keys skipped: default_controller, 404_override, translate_uri_dashes

2. Convention routes synthesized from every public method on each controller in application/controllers/**. CI3 routes by convention much more than via routes.php, so without this the graph would be near-empty for typical projects. URLs are lowercased per CI3 routing rules; _-prefixed methods, __construct, __destruct are excluded. Recognized controller bases: CI_Controller, MX_Controller (HMVC), MY_Controller, REST_Controller, plus common project-specific patterns (Admin_Controller, Public_Controller, Frontend_Controller, Backend_Controller).

3. Magic-loaded models and libraries — both $this->load->model('X') / $this->load->library('X') calls and the runtime property accesses that follow ($this->ModelName->method()). This is the part that matters most in practice: on a real ~8k-PHP-file CI3 codebase, only ~0.2% of model usages are explicit load->model() calls; the rest are property accesses on pre-loaded models that pure AST analysis can't see. The resolver filters on PascalCase to keep CI3 built-in properties ($this->load, $this->db, $this->input, …) out — they're all lowercase.

Reference resolution

controller/method strings in routes.php resolve to method nodes in application/controllers/, trying both PascalCase (CI3 file-naming convention) and the literal segment as fallback.

Tests

13 new tests in __tests__/frameworks.test.ts:

• Explicit routes: tuple syntax, verb-scoped variant, reserved-key filtering
• Convention routes: visibility filters (public only, _-prefix excluded), index → URL base, subdirectory URL building, non-controller files, HMVC base classes
• Loader extraction: load->model('X'), load->library('X'), dedup, lowercase → PascalCase normalization
• Magic property access: $this->Foo->bar() captured, lowercase built-ins ($this->db, $this->session, $this->load) excluded
• Dedup across both layers when both patterns coexist

All 81 tests across frameworks.test.ts, resolution.test.ts, and frameworks-integration.test.ts pass. tsc --noEmit clean.

Validation on a real CI3 codebase

Indexed an ~8k-PHP-file CI3 project (61k PHP files total before filters):

Metric	Value
Cold index time	~52s (~180 files/s)
Incremental sync after 1-file touch	~0.3s
Route nodes emitted	2,528
Files reachable from a specific model (Restomodel) via the graph	465
Same count from grep	467

99.6% recall vs grep, with edges that grep can't give you (resolves through the framework, not just text matches).

Notes

• Changelog entry placed under ## [Unreleased] rather than a specific version — easier to rename at release time.
• No version bump in package.json / package-lock.json — leaving release cadence to you.
• Edit edge kind chosen as imports for consistency with how Laravel emits its handler references; the resolution pipeline routes these through the standard name-matcher.

Test plan

• npm test — 81/81 framework + resolution + integration tests pass
• npx tsc --noEmit — clean
• End-to-end indexing on a real CI3 project, manual verification of route/import counts
• Manual smoke test on a small Laravel project (no regressions in laravelResolver) — not run here, but the changes are additive and laravel.ts is untouched