docs: Consolidate coding rules and strengthen test policy

[KATO-Hiro]

close #3290

• coding-style.md: Add No Hard-Coded Values, Function Ordering, and Svelte 5 docs sections
• coding-style.md: Absorb content from svelte-docs.md (now redundant)
• svelte-docs.md: Delete (merged into coding-style.md)
• testing.md: Add 'Tests Ship with the Implementation' section

Summary by CodeRabbit

• Documentation
  • Updated development guidelines: no hard-coded values, prescribed function ordering, and guidance to consult official Svelte 5 docs when behavior is unclear.
  • Removed a now-obsolete Svelte docs metadata file and reorganized how Svelte references are handled.
• Tests
  • New rule: tests must be included with the implementing commit; “add tests later” is disallowed for non-trivial logic.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e74469fc-441f-4cb2-b74a-8c19055ef8f5

📥 Commits

Reviewing files that changed from the base of the PR and between 6070f55 and 7b8e05e.

📒 Files selected for processing (1)

• .claude/rules/coding-style.md

✅ Files skipped from review due to trivial changes (1)

• .claude/rules/coding-style.md

---

Walkthrough

Three documentation files under .claude/rules/ were changed: coding-style.md was expanded with three new sections, svelte-docs.md was removed, and testing.md gained a requirement that tests be committed alongside their implementation.

Changes

Cohort / File(s)	Summary
Coding Style Guidelines ​.claude/rules/coding-style.md	Inserted three new sections: "No Hard-Coded Values" (extract magic numbers/strings into named constants with examples), "Function Ordering" (prescribed in-file declaration order: exported APIs first, then helpers), and "Svelte 5: Prefer Official Docs Over Training Knowledge" (instructs using WebFetch to consult official Svelte docs with a URL pattern).
Documentation Removal ​.claude/rules/svelte-docs.md	Deleted the file that previously documented Svelte official docs metadata and example WebFetch URL mappings for Svelte 5 guidance.
Testing Requirements ​.claude/rules/testing.md	Added a rule requiring tests be included in the same commit as the implementation; explicitly disallows deferring tests and mandates tests for non-trivial logic even when not specified in tasks.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐇 I hopped through rules with nimble paws,
Pulled magic numbers from secret laws,
Lined up functions tidy and neat,
Paired tests with code — no skipped-beat feat,
Svelte docs guide my careful claws.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main changes: consolidating coding rules (merging svelte-docs.md into coding-style.md) and strengthening the test policy.
Linked Issues check	✅ Passed	The PR successfully addresses issue #3290 by updating coding-style.md with new sections, absorbing and deleting svelte-docs.md, and enhancing testing.md policy.
Out of Scope Changes check	✅ Passed	All changes are directly related to consolidating rules and strengthening test policy as described in the PR objectives and linked issue.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch #3290

📝 Coding Plan

• Generate coding plan for human review comments

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

.claude/rules/testing.md (1)

16-20: Clear policy, but "non-trivial logic" could use examples.

The requirement to ship tests with implementation is well-stated and aligns with best practices. However, "non-trivial logic" on line 20 is subjective. Consider adding brief examples to help developers consistently determine when tests are required.

📝 Suggested clarification

 ## Tests Ship with the Implementation
 
 Tests must be included in the same commit as the implementation they cover. "Add tests later" is not acceptable — a feature or fix is not done until its tests pass.
 
-If a task description does not mention tests, add them anyway for any non-trivial logic.
+If a task description does not mention tests, add them anyway for any non-trivial logic (e.g., calculations, conditionals, data transformations, API calls). Trivial pass-through code (simple getters, type definitions) may be exempt.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In @.claude/rules/testing.md around lines 16 - 20, The guideline "Tests Ship
with the Implementation" is clear but the phrase "non-trivial logic" is
ambiguous; update the section (header "## Tests Ship with the Implementation"
and the sentence containing "non-trivial logic") to include 2–3 short concrete
examples (e.g., business rules, data transformation functions, API handlers,
performance-sensitive code) that illustrate when tests are required, and add a
one-line rule-of-thumb (e.g., "if code affects customer-visible behavior, shared
libraries, or complex algorithms, include tests") so readers can consistently
determine when to add tests.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In @.claude/rules/coding-style.md:
- Around line 89-97: The "Function Ordering" section is ambiguous about whether
helpers are interleaved with or separated from exports; update the text under
the "Function Ordering" heading to explicitly choose and describe Option A
(interleaved): state that exported functions/classes should appear in public API
order and each exported symbol's internal helpers should follow immediately
(e.g., exportFoo → helperFoo1, helperFoo2 → exportBar → helperBar1), remove or
replace the numbered list that implies all exports first, and add one short
example sentence clarifying that helpers must not be collected at the end of the
file.

---

Nitpick comments:
In @.claude/rules/testing.md:
- Around line 16-20: The guideline "Tests Ship with the Implementation" is clear
but the phrase "non-trivial logic" is ambiguous; update the section (header "##
Tests Ship with the Implementation" and the sentence containing "non-trivial
logic") to include 2–3 short concrete examples (e.g., business rules, data
transformation functions, API handlers, performance-sensitive code) that
illustrate when tests are required, and add a one-line rule-of-thumb (e.g., "if
code affects customer-visible behavior, shared libraries, or complex algorithms,
include tests") so readers can consistently determine when to add tests.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 2a97d8e4-de24-4da4-9c58-edaf2202ff47

📥 Commits

Reviewing files that changed from the base of the PR and between 26117af and 6070f55.

📒 Files selected for processing (3)

• .claude/rules/coding-style.md
• .claude/rules/svelte-docs.md
• .claude/rules/testing.md

💤 Files with no reviewable changes (1)

• .claude/rules/svelte-docs.md

[KATO-Hiro]

LGTM