bugfix - prevent imported static initialization deadlocks (#680)

[dannymeijer]

Summary

This PR fixes imported static initialization deadlocks by making generated static access call the defining module's static-init guard before forcing an imported LazyLock. It also chains that guard through public static re-export modules, merges the current origin/release/v0.3 state into the branch, and bumps the v0.3 release candidate to 0.3.0-rc16.

Type of change

• Bug fix
• New feature
• Refactor / maintenance
• Documentation
• CI / tooling
• RFC (adds/updates docs/RFCs/*)

Area(s)

Select the primary areas touched (used for review routing; labels are managed separately):

• Incan Language (syntax/semantics)
• Compiler (frontend/backend/codegen)
• Tooling (CLI/formatter/test runner)
• Editor integration (LSP/VS Code extension)
• Runtime / Core crates (stdlib/core/derive)
• Documentation

Key details

• User-facing behavior: Imported source statics can be used from other modules without deadlocking when their initializer calls back into the defining module's static initialization path. InQL-style shared registry statics are unblocked for decorator-driven helper modules.
• Internals: Static access emission now tracks imported static bindings and routes reads, bindings, storage-rooted field/index operations, and assignments through a per-static init call plan. Public re-export modules import and chain the original defining module's __incan_init_module_statics helper.
• Risks: Static initialization is shared generated-runtime plumbing. The fix touches core static emission paths, so the PR includes focused deadlock coverage, existing static/codegen snapshots, and the full pre-commit gate after merging upstream.

Testing / verification

• make test / cargo test
• make examples (if relevant)
• incan fmt --check . (if relevant)
• Manual verification described below

Manual verification notes:

• cargo test test_imported_static_initializer_does_not_deadlock_issue680 --features cli --test integration_tests
• cargo test --features cli --test codegen_snapshot_tests
• git diff --check
• make pre-commit

Docs impact

• No docs changes needed
• Docs updated
• Docs follow Divio intent (tutorial/how-to/reference/explanation) where applicable

If docs updated:

• Link(s): n/a

Checklist

• I kept public docs user-focused and moved internals to contributing docs when appropriate
• I avoided duplicating canonical install/run instructions in multiple places
• I added/updated tests where it materially reduces regressions

Closes #680