fix(i18n): correct Catalan (ca) locale and add ca glossary

[Qjammer]

Issue for this PR

Closes #42837

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

I'm a native Catalan speaker. The ca locale added in #40992 has strings that say something
different from the English, not merely awkward ones:

Key	English	Was	What it said
ui.basicTool.called	Called {{tool}}	Es diu {{tool}}	"it is named", not invoked
settings.general.row.showCustomAgents.title	Show agent	Agent d'espectacles	"entertainment agent"
provider.connect.method.apiKey (×4)	API key	tecla API	"API keyboard-key"
settings.general.row.shell.title	Terminal shell	Carcassa terminal	"terminal casing"
context.stats.inputTokens (×6)	Input Tokens	Fitxes d'entrada	"input filing-cards"
context.breakdown.tool	Tool Calls	Trucades d'eines	"phone calls of tools"

Three self-inconsistencies too: shell was rendered five different ways; web switched gender
inside a single popover; and workspace.resetting.title / workspace.reset.success.title were
byte-identical, so in-progress and finished were indistinguishable.

The rest is grammar. Catalan uses the singular imperative for menu and button labels, and the
vós plural for messages addressed to the user (Softcatalà style guide, Formes verbals). The
locale mixed them arbitrarily — desktop.menu.restart was Reinicieu in packages/app but
Reinicia in packages/desktop. Labels that used the infinitive (Tancar, Enviar, Publicar,
Desfer, Tallar) are now imperatives — Catalan doesn't allow the infinitive for commands. Bare
gerunds became S'està….

244 values changed across the three files. No English string or key is touched.

I also added .opencode/glossary/ca.md, which is arguably the actual fix:
.opencode/command/translate.md loads .opencode/glossary/<locale>.md when present, and Catalan
was translated without one while 16 other locales have theirs. Term choices there are backed by the
Catalan translation memories Softcatalà publishes (KDE, GNOME, LibreOffice, Microsoft Terminology,
Chromium) plus Git's for Git vocabulary, with segment counts cited per row so each can be checked
without reading Catalan. Happy to split it into its own PR if you'd rather review them separately.

How did you verify your code works?

No behaviour changes, so I verified structure and consistency rather than runtime:

• Key sets still match en.ts exactly — nothing added, removed or renamed. The only extras
  are the Catalan CLDR .many plural forms English doesn't have, and the desktop.* keys every
  locale already carries.
• Placeholders preserved. Every {{var}} and \n matches the English for all 1,246 keys that
  have an English counterpart. The 8 .many keys have no English counterpart, so I checked those
  against their own .one/.other siblings instead.
• All three files parse.
• The repo's own i18n tests pass against this branch: packages/app/src/i18n/parity.test.ts
  (5 pass, 979 assertions) and packages/app/src/i18n/desktop-native.test.ts (8 pass, 455
  assertions). parity.test.ts is the locale-coverage test and already lists ca. I couldn't run
  packages/ui/src/context/i18n.test.ts locally as it needs React installed, but it covers the
  i18n machinery rather than locale content, which this PR doesn't touch.

Easiest confirmation for a reviewer: git diff --stat shows the three locale files at +166/−166,
+70/−70 and +8/−8 — exactly balanced, so only values changed and nothing structural.

Screenshots / recordings

N/A — locale strings only, no layout or component changes.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

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No duplicate PRs found.

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