Redesign Galápagos theme — clarify dark teal-sea identity

[gregpriday]

Summary

The Galápagos theme is a dark teal-sea theme inspired by the volcanic islands. The surface palette is good, but the syntax highlighting palette lacks coherence, several terminal colors are indistinguishable from each other, and the theme's identity isn't clearly expressed in its accent and highlight choices.

Problem Statement

Galápagos uses #131A1C canvas and #0F1416 sidebar — a dark teal-charcoal that works well. The issues are in the detail layers:

• syntax-punctuation: #6E8690 is very close to syntax-comment: #7D9194 — both are mid-grey teal, making code comments and punctuation look nearly identical. Code becomes hard to parse at a glance.
• syntax-keyword: #4ECDC8 (a bright cyan-teal) and syntax-operator: #8BBFC8 (a lighter blue-teal) are both in the cyan family. With the teal surface background, these syntax roles merge visually with the environment rather than standing out from it.
• terminal-yellow: #9B8E67 and terminal-green: #3F9366 are both muted and dark — they risk failing contrast against the Galápagos canvas. terminal-blue: #6585A4 and terminal-cyan: #528B8B are similarly dark.
• activity-active and activity-working both use #22c55e — the standard Canopy green. On a teal-dark surface this works but feels generic. The Galápagos could have a more adapted "tropical water" active color (e.g. a brighter cyan) while keeping the same semantic meaning.
• The syntax-chip: #C8A055 is a warm amber that appears isolated — it's the only warm-toned token in an otherwise cool palette, making it look out of place.
• The theme's identity (volcanic islands, tropical ocean, iguana green) is not coherently expressed. The palette reads as "generic teal dark" rather than specifically Galápagos.

Relevant code:

• shared/theme/themes.ts#L505-L566 — current Galápagos token definitions

Desired Behavior

Galápagos should feel like the deep Pacific: dark volcanic surfaces with bright tropical-water teal and cyan highlights, and the occasional marine life amber-green. It should:

• Have clearly differentiable syntax categories — especially punctuation vs. comment, and keyword vs. operator.
• Terminal ANSI colors should all pass ≥ 3:1 contrast against the canvas.
• The cool teal palette should be coherent throughout — warm intrusions (like the amber chip) should either be removed or integrated into a narrative.
• The theme should be immediately distinguishable from Fiordland (darker, colder, more angular) in a side-by-side comparison.

Verification Workflow

1. Apply: await setAppTheme(window, "galapagos").
2. Screenshot + contrast measurement.
3. Measure all 8 normal ANSI terminal colors against canvas.
4. AI visual review: does the theme convey tropical ocean? Is it distinct from Fiordland? Are syntax roles differentiable?
5. npm run check.

Acceptance Criteria

• syntax-punctuation and syntax-comment are visually distinct (different hue or at least 20% lightness difference).
• syntax-keyword and syntax-operator are visually distinct.
• All 8 normal ANSI terminal colors achieve ≥ 3:1 contrast against surface-canvas.
• The theme reads as a coherent tropical-ocean dark theme, distinct from Fiordland, in screenshot evaluation.
• All E2E tests pass.

Edge Cases & Risks

• Terminal scheme pairing from PR feat(terminal): match terminal color scheme to app theme automatically #3345 — verify app/terminal visual pairing after changes.
• Category label colors (category-*) use the shared dark-theme defaults; if the redesign makes the theme strongly teal, verify the blue/cyan category labels still read as distinct from the overall chrome.

[gregpriday]

Terminal color scheme — review as part of redesign

The APP_THEME_TERMINAL_SCHEME_MAP currently maps galapagos → github-dark (GitHub Dark). As part of this theme redesign, review whether the terminal color scheme still pairs well with the updated app surfaces:

1. Evaluate the current pairing — after updating the surface/accent tokens, check whether GitHub Dark still feels cohesive. If the surface palette shifts significantly, the terminal may look disconnected.
2. Research alternatives — search for well-known open-source terminal color schemes whose character matches the redesigned theme. Evaluate candidates for ANSI color legibility against the new surface background, not just aesthetic similarity.
3. Consider a bespoke scheme — if no existing scheme is a tight fit, create a dedicated one derived from the redesigned app tokens (like we did for Daintree via getTerminalThemeFromAppScheme). This gives the tightest visual integration.
4. Adapt rather than copy — if borrowing an open-source palette, adjust selection background, cursor, and bright variants so they harmonize with the app's surface/accent tokens.

Update APP_THEME_TERMINAL_SCHEME_MAP in src/config/terminalColorSchemes.ts and add any new scheme to the BUILT_IN_SCHEMES array. Update the test count in src/config/__tests__/terminalColorSchemes.test.ts if adding a new scheme.