Add go-to-definition support for BIG archive virtual files

[ViTeXFTW]

Summary

• Canonicalize big: URIs so archive-backed virtual files resolve consistently across clients.
• Allow server and VS Code clients to open, inspect, and navigate into read-only files inside .big archives.
• Extend the E2E and extension smoke tests to cover archive URI encoding, virtual file reads, and definition lookup from both loose files and archived INI files.
• Document that loose files open through file: URIs while archive contents use big: URIs.

Testing

• cargo test -p zerosyntax-server or the server test coverage added in crates/server/src/backend.rs.
• python crates/server/tests/e2e.py target/debug/zerosyntax-lsp.exe.
• VS Code extension smoke test updated in editors/vscode/src/test/suite/smoke.test.ts.
• Not run in this environment.

[greptile-apps]

Greptile Summary

Adds canonical big: URI handling and VS Code support for opening, inspecting, and navigating archive-backed virtual INI files.

• Canonicalizes archive URIs at virtual-file and document lookup boundaries.
• Registers archived INI documents with the VS Code language client.
• Extends server E2E and extension smoke coverage for archive reads and definitions.
• Documents the distinction between loose file: resources and archived big: resources.

Confidence Score: 5/5

The PR appears safe to merge with no concrete changed-code defects identified.

URI normalization is consistently applied across document lifecycle, virtual-file reads, and definition lookups, while the added tests cover scanner-form and VS Code-form archive URIs.

T-Rex Logs

What T-Rex did

• The target command was executed in the captured working directory and completed with exit code 0.
• Verified that BIG definitions open through encoded read-only URIs and can be navigated.
• Confirmed that ALL E2E CHECKS PASSED according to the log.
• Inspected the execution log artifact to verify the exact command, working directory, and exit status.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
crates/server/src/backend.rs	Adds consistent BIG URI canonicalization to document and virtual-file lookup paths, with focused normalization tests.
crates/server/tests/e2e.py	Adds end-to-end coverage for archive indexing, URI variants, virtual reads, and definition navigation.
editors/vscode/src/extension.ts	Extends the language-client document selector to archive-backed generals-ini documents.
editors/vscode/src/test/runTest.ts	Generates a BIG archive fixture and configures it as a base INI root for extension tests.
editors/vscode/src/test/suite/smoke.test.ts	Exercises definitions into and within archived virtual documents through VS Code.
docs/language-server.md	Documents URI schemes and read-only navigation behavior for loose and archived definitions.

_{Reviews (1): Last reviewed commit: "Support navigation into BIG archive virt..." | Re-trigger Greptile}