fix(web): persist usage page environment selection

[AmoonPod]

What Changed

The Usage page already remembered the last metric and time window between visits. This PR extends the same t3code:usage-page-preferences:v1 localStorage record with the environment selection, so a custom set of selected environments is restored on the next visit.

• usagePagePreferences.ts: the preferences schema gains an optional selectedEnvironmentIds field. null (the default) means "all environments", including ones connected later; an array is an explicit subset, an empty array means nothing is selected. Two small helpers convert between the stored shape and the ReadonlySet the page uses.
• UsagePage.tsx: the initial selection is restored from preferences, and every selection change (including switching back to all environments) is saved. Changing metric or window preserves the selection instead of dropping it.

Why

The environment picker was the only Usage page state not persisted. Users with the same providers connected on multiple machines see duplicated provider rows across environments, and deselecting the duplicates on every visit was tedious. This follows the existing pattern the page uses for metric/window persistence, with no new storage keys and graceful decoding of preferences saved before this field existed.

UI Changes

None. No visible element changed; only which environments are pre-selected when the page opens.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes (not applicable - no visual change)
• I included a video for animation/interaction changes (not applicable)

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Model: openrouter/z-ai/glm-5.3-flash. Harness: OpenCode (T3 Code).

Summary by CodeRabbit

• New Features

  • Usage page environment filter selections are now saved and restored across visits.
  • Explicit environment selections, deselections, and the all-environments option are remembered.

• Bug Fixes

  • Improved handling of saved usage preferences, including older, invalid, or incomplete preference data.
  • Environment selections are cleaned up to prevent duplicate or blank entries.

[macroscopeapp]

Approvability

Verdict: Approved at cd35c6a

Macroscope's review found this PR approvable — This is a focused Usage-page fix that persists an already user-selected environment subset in the existing localStorage record while preserving the prior all-environments default and legacy preferences. The production change is isolated and covered by compatibility and round-trip tests, with no API, deployment, security, billing, or static-analysis configuration changes.

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[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 6c58362 and cd35c6a.

📒 Files selected for processing (3)

• apps/web/src/components/usage/UsagePage.tsx
• apps/web/src/components/usage/usagePagePreferences.test.ts
• apps/web/src/components/usage/usagePagePreferences.ts

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📝 Walkthrough

Walkthrough

The usage page now persists selected environment IDs in usage preferences. Preferences support normalized environment selections, legacy data, defaults, and storage failures. The page restores saved selections and saves changes from environment, metric, and time-window controls.

Changes

Usage preference persistence

Layer / File(s)	Summary
Preference schema and conversions apps/web/src/components/usage/usagePagePreferences.ts, apps/web/src/components/usage/usagePagePreferences.test.ts	Preferences now store optional environment IDs. Conversion helpers trim, filter, deduplicate, and preserve null for all environments. Tests cover defaults, legacy data, invalid data, conversion behavior, and storage failures.
Usage page environment persistence apps/web/src/components/usage/UsagePage.tsx	The page restores saved environment selections and persists changes made through environment, metric, and time-window controls.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to cd35c

The Usage page now restores and saves environment filters alongside existing preferences, including all-environments and empty selections. Existing saved preferences remain compatible, with no concrete merge-blocking risk identified.

Sequence Diagram(s)

sequenceDiagram
  participant UsagePage
  participant PreferenceHelpers
  participant PreferenceStorage
  UsagePage->>PreferenceStorage: Read saved usage preferences
  PreferenceStorage-->>UsagePage: Return selectedEnvironmentIds
  UsagePage->>PreferenceHelpers: Convert stored IDs to a selection set
  PreferenceHelpers-->>UsagePage: Return selected environments
  UsagePage->>PreferenceHelpers: Convert selection set to stored IDs
  PreferenceHelpers-->>UsagePage: Return normalized IDs
  UsagePage->>PreferenceStorage: Save updated usage preferences

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Suggested reviewers: extoci

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 3 files.	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 and concisely describes the main change: persisting the Usage page environment selection.
Description check	✅ Passed	The description includes complete What Changed, Why, UI Changes, and Checklist sections. It explains the storage behavior, compatibility, scope, and testing-related considerations.
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.

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