refactor(config): born-valid options, layered decode, drop mirrors

[16bit-ykiko]

What

Unifies the config system around one set of structs and one decode mechanism, then simplifies everything that existed to work around the old split.

One struct set. Feature options structs (CodeCompletionOptions, InlayHintsOptions) now double as their clice.toml / initializationOptions sections: every field is defaulted<T> with its default as the field initializer. The all-optional mirror structs (InlayHintsConfig, CodeCompletionConfig) are deleted, along with all three hand-written field-by-field overlay blocks (apply_defaults, the compiler copy sites, inspect's --config parser). Adding a new option key is now a one-line change.

Born-valid Config. A default-constructed Config is fully valid — no two-phase init, with_defaults() is gone. apply_defaults() shrinks to finalize(): derived paths, ${workspace} substitution, canonicalization, rule glob compilation, and validation (an explicit zero worker count / memory budget is warned and reset — it was previously a silent auto sentinel).

Layering is the decode. Config sources are decoded sequentially onto one object (clice.toml, then initializationOptions); the decoder only touches named fields and nested sections merge per field. This is the mechanism the server already used for the initializationOptions overlay — the refactor removes everything that duplicated it.

Workers carry the whole Config. QueryParams/BuildParams lose their per-feature forwarded option fields (inlay_options, completion_options) and carry one Config; features read their own section. No per-feature forwarding field is ever added again.

Also: the dead project.max_active_file knob is removed (it had no reader; unknown keys in existing configs surface as a warning, not an error), and the tiny document_link.h / inactive_regions.h headers are folded into feature.h.

Compatibility

No key renames — existing clice.toml files and initializationOptions payloads behave identically, except max_active_file (now an unknown-key warning) and explicit zero worker counts (now warned and reset instead of silently corrected).

Tests

New unit tests pin the load-bearing semantics: section deep-merge across TOML/JSON layers (including a field set in both — later source wins), JSON null on an option is a decode error, typos inside feature sections still warn, the full born-valid default surface, and zero-value validation. All four suites pass on RelWithDebInfo plus unit tests under Debug (ASan + assertions); the snap suite passes with zero snapshot diffs, confirming the wire behavior is unchanged.

[coderabbitai]

📝 Walkthrough

Walkthrough

Changes

Configuration and feature refactor

Layer / File(s)	Summary
Configuration defaults and finalization src/server/state/config.*, src/server/state/workspace.h, src/server/transport/master_server.cpp, src/server/transport/lsp_client.cpp, tests/unit/server/config_tests.cpp, docs/...	Configuration fields now have concrete defaults. Config::finalize validates and derives values after overlays. The obsolete max_active_file option and with_defaults APIs were removed.
Feature option and scanning contracts src/feature/feature.h, src/feature/inactive_regions.cpp, src/index/preamble_state.h, src/driver/inspect.cc, tests/unit/feature/inactive_region_tests.cpp	Feature options use defaulted fields. DocumentLink and InactiveScan are declared in feature.h, and inactive-region API consumers use the consolidated header.
Workspace configuration propagation src/server/protocol/worker.h, src/server/compiler/compiler.cpp, src/server/worker/*.cpp, src/server/compiler/indexer.cpp, src/server/service/query.cpp	Query and build requests carry complete workspace configuration. Workers and indexing services read validated configuration values directly.

Estimated code review effort: 4 (Complex) | ~45 minutes

Possibly related PRs

• clice-io/clice#423: Related configuration defaults and feature-option centralization.
• clice-io/clice#456: Related configuration loading and finalization changes.
• clice-io/clice#501: Related DocumentLink and InactiveScan API consolidation.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 4.84% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the configuration refactor, including born-valid options, layered decoding, and removal of mirror structures.
Description check	✅ Passed	The description directly explains the configuration refactor, compatibility changes, worker updates, removed settings, and added tests.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/config-born-valid

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/feature/feature.h`:
- Around line 310-318: Update inactive_regions() directive traversal in
inactive_regions.cpp to process only directives within the requested
[resume_offset, end_offset) scan interval before updating stack or serializing
regions. Ensure pending regions are closed at end_offset, and add coverage for
both bounded scans and resumed scans so directives outside the interval do not
affect results.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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Run ID: 26e7162a-01ad-418b-85df-40832a4497a2

📥 Commits

Reviewing files that changed from the base of the PR and between 55313da and af01b4f.

📒 Files selected for processing (26)

• docs/clice.toml
• docs/en/dev/contribution.md
• docs/en/guide/configuration.md
• docs/zh/dev/contribution.md
• docs/zh/guide/configuration.md
• src/driver/inspect.cc
• src/feature/document_link.h
• src/feature/feature.h
• src/feature/inactive_regions.cpp
• src/feature/inactive_regions.h
• src/index/preamble_state.h
• src/server/compiler/compiler.cpp
• src/server/compiler/indexer.cpp
• src/server/protocol/worker.h
• src/server/service/query.cpp
• src/server/state/config.cpp
• src/server/state/config.h
• src/server/state/workspace.h
• src/server/transport/lsp_client.cpp
• src/server/transport/master_server.cpp
• src/server/worker/stateful_worker.cpp
• src/server/worker/stateless_worker.cpp
• tests/unit/feature/inactive_region_tests.cpp
• tests/unit/index/tu_index_tests.cpp
• tests/unit/server/config_tests.cpp
• tests/unit/server/query_overlay_tests.cpp

💤 Files with no reviewable changes (7)

• src/feature/document_link.h
• src/feature/inactive_regions.h
• docs/zh/guide/configuration.md
• tests/unit/server/query_overlay_tests.cpp
• tests/unit/index/tu_index_tests.cpp
• docs/clice.toml
• docs/en/guide/configuration.md