show cached input hint with input/output tokens (codex style)

[MRNAQA]

Summary

• keep the existing Session input/output tokens layout instead of expanding it into new cache-specific columns
• append cached input in parentheses next to the input amount when cache data is present
• update compact/sidebar formatting and focused tests to preserve the old visual shape while making cache usage explicit
• document the showSessionTokens behavior in the README

Linked Issue

• No linked issue. This is a small, user-facing clarification to make session token semantics match the underlying cache-aware accounting without changing the established layout.

OpenCode Validation

• Tested against OpenCode 1.14.39
• Verified behavior against cache-aware session token data paths already exposed by the plugin's quota stats layer
• Local OpenCode config was switched to a tarball build from this branch for follow-up manual verification

Quality Checklist

• npm run build
• npm run typecheck
• npm test -- --run tests/session-tokens-format.test.ts tests/format.test.ts tests/quota-command-format.test.ts tests/tui-sidebar-format.test.ts tests/tui-compact-format.test.ts tests/quota-stats.test.ts
• Updated README for the user-facing session token behavior

[Copilot]

Pull request overview

This PR extends the session token summary model to carry cached input and combined (new + cached) input totals, and updates the various renderers (full rows, sidebar summary, and compact/TUI status line) to display a richer token breakdown when cache data is present.

Changes:

• Add cachedInput and totalInput to per-model session token rows, plus aggregate totalCachedInput and totalCombinedInput.
• Update session token formatting to render new, cache, in (combined), and out where applicable, including compact/sidebar variants.
• Update/extend tests to lock in the new display semantics across formats.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/tui-sidebar-format.test.ts	Updates sidebar expectations to include new/cache/combined token display.
tests/tui-compact-format.test.ts	Updates compact status line expectations for cache-aware token breakdown.
tests/session-tokens-format.test.ts	Adds coverage for cache-aware rendering in both detailed and sidebar-summary renderers.
tests/quota-command-format.test.ts	Updates /quota output expectations to include cache breakdown.
tests/format.test.ts	Adds coverage for cache-aware session token rendering in single/all window toast formats.
src/lib/tui-compact-format.ts	Renders cache-aware token segment in the compact/TUI status line.
src/lib/session-tokens.ts	Threads cache/combined totals through the display fetch result.
src/lib/session-tokens-format.ts	Implements cache-aware formatting for detailed + compact + sidebar-summary session token sections.
src/lib/quota-stats.ts	Aggregates cached input and combined input in getSessionTokenSummary.
src/lib/entries.ts	Extends the session token data interfaces to include cached + combined input fields.

[slkiser]

@MRNAQA Thanks for the contribution