Update Config Document

Update Configuration Documentation

Given a new or changed key in subx-core/src/config/, confirm the coverage matrix in docs/config-usage-analysis.md has a row for it and that the row's status is correct.

The call-hierarchy line numbers in this document are a dated historical record and are NOT maintained — the document's own header declares this. Do not re-derive or "refresh" them; doing so reverses the document's declared demotion. Current behaviour lives in docs/configuration-guide.md.

Target Files

• Primary document to update: docs/config-usage-analysis.md
• Secondary document to update (after primary is done): README.md
• Source of truth for configuration items: subx-core/src/config/ (structs, defaults, validation — the configuration crate half of the two-crate split) and all their consumers across subx-core/src/ and src/ (the CLI half).

Workflow

Work one configuration item at a time. Do not batch updates across items.

1. Read the Current Document

Load docs/config-usage-analysis.md first. Treat its existing contents as potentially outdated; every field must be re-verified against the code.

2. For Each Configuration Item, Do All of the Following

1. Verify correctness and relevance. Confirm the item still exists in subx-core/src/config/ with the same name, type, default, and semantics.

2. Identify the real "Actual Usage Location".

   • Search for every production call site that reads the value.
   • Follow the chain: when a config value is assigned to a struct field, continue searching for uses of that struct field. A field that is written but never read is effectively unused — flag it.
   • Ignore all references that appear only in unit tests, integration tests, test helpers, #[cfg(test)] blocks, or the tests/ directory. Only production-level usage counts.

3. Exclude items that are obviously set only through the subx-cli config subcommand. These CLI-plumbing entries do not need their own doc row.

4. Update the document immediately after verifying this item. Do not accumulate edits across multiple items — commit each correction to the file as soon as it is established. This keeps progress auditable and recoverable if the session is interrupted.

3. Discover Undocumented Items

Scan subx-core/src/config/ for configuration fields that are not represented in docs/config-usage-analysis.md. For every missing item, append a new entry following the existing document's format and conventions.

4. Sync the README

Once every configuration item has been validated and the document fully reflects the current code, update README.md so the subcommand and configuration user-facing documentation matches the audited matrix.

Rules and Reminders

• All documentation updates are written in English, matching the project convention for docs and code comments.
• Do not mark items as deprecated. If a configuration item is no longer used in production, report it to the user for removal instead of silently keeping a dead entry.
• Never rewrite the call-tree ("呼叫樹") blocks: their line numbers are the dated record described above. A new row records its usage sites by path and function, not by line number.
• Proceed methodically and incrementally: verify, update the doc, move on.