docs: update all package READMEs to match gt repo style

[moss-bryophyta]

Updates all 7 package READMEs to follow the same format as the gt monorepo:

• Centered logo with light/dark mode support
• Documentation + Report Bug links
• One-liner description
• Installation command
• Quick start example (where applicable)
• Link to full docs

Keeps all experimental warnings.

Greptile Summary

This PR standardizes all 7 package READMEs in the gt-python monorepo to match the gt repo style — adding a centered logo with light/dark mode support, documentation and bug-report links, a one-liner description, installation commands, and minimal Quick Start examples. The changes are purely cosmetic/documentation, with one notable exception.

Key findings:

• The gt-i18n Quick Start example imports and calls init_gt, which does not exist in the gt_i18n package. This would produce an ImportError for any user following the example. The correct initialization path uses I18nManager + set_i18n_manager.
• The light/dark mode <picture> element pattern is correctly implemented across all files: <source> targets light mode, and the <img> fallback serves the dark logo.
• Significant API reference documentation was removed from generaltranslation-icu-messageformat-parser and generaltranslation-intl-messageformat in favour of pointing users to the full docs site — this is consistent with the stated goal but worth being aware of if the docs site is not yet comprehensive.
• The gt-fastapi and gt-flask Quick Start examples correctly reflect the actual exported initialize_gt and t API.

Confidence Score: 3/5

• Safe to merge after fixing the non-existent init_gt function in the gt-i18n Quick Start example.
• All changes are documentation-only and look correct across 6 of 7 files. The gt-i18n README introduces a broken Quick Start that references a function (init_gt) that does not exist in the package, which will mislead users.
• packages/gt-i18n/README.md — Quick Start uses a non-existent init_gt function.

Important Files Changed

Filename	Overview
packages/gt-i18n/README.md	Adds styled header and Quick Start, but the Quick Start imports init_gt which doesn't exist in the package — this would cause an ImportError for anyone following the example.
packages/gt-fastapi/README.md	Adds styled header, one-liner description, and Quick Start. The initialize_gt and t imports match the actual package exports.
packages/gt-flask/README.md	Adds styled header, one-liner description, and Quick Start. The initialize_gt and t imports match the actual package exports.
packages/generaltranslation-icu-messageformat-parser/README.md	Adds styled header and trims extensive API docs to a minimal Quick Start; no technical inaccuracies introduced.
packages/generaltranslation-intl-messageformat/README.md	Adds styled header and reduces to a minimal Quick Start; imports and usage match the actual package API.
packages/generaltranslation-supported-locales/README.md	Adds styled header and a one-liner description with installation command. No Quick Start for this utility package, which is appropriate.
packages/generaltranslation/README.md	Adds styled header, one-liner description, and installation command with a link to the full docs. No issues.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[User reads README] --> B{Which package?}
    B --> |gt-fastapi| C["from gt_fastapi import initialize_gt, t ✅"]
    B --> |gt-flask| D["from gt_flask import initialize_gt, t ✅"]
    B --> |gt-i18n| E["from gt_i18n import t, init_gt ❌"]
    C --> F["initialize_gt(app, ...)"]
    D --> G["initialize_gt(app, ...)"]
    E --> H["init_gt(...) → ImportError"]
    H --> I["Correct API: I18nManager + set_i18n_manager"]

Loading

Prompt To Fix All With AI

This is a comment left during a code review.
Path: packages/gt-i18n/README.md
Line: 29-33

Comment:
**`init_gt` does not exist in `gt_i18n`**

The Quick Start imports and calls `init_gt`, but this function is not exported from `gt_i18n` and does not exist anywhere in the package. Running this example would raise an `ImportError`.

The `gt_i18n` package exports `I18nManager` and `set_i18n_manager` for initialization, not an `init_gt` function. Framework-specific setup is handled by `initialize_gt` from `gt-fastapi` / `gt-flask` — there is no equivalent standalone `init_gt` in `gt_i18n`.

```suggestion
```python
from gt_i18n import I18nManager, set_i18n_manager, t

manager = I18nManager(default_locale="en", locales=["en", "es", "fr"])
set_i18n_manager(manager)

print(t("Hello, world!"))
```
```

How can I resolve this? If you propose a fix, please make it concise.

_{Last reviewed commit: "docs: update all pac..."}

Greptile also left 1 inline comment on this PR.

[greptile-apps]

init_gt does not exist in gt_i18n

The Quick Start imports and calls init_gt, but this function is not exported from gt_i18n and does not exist anywhere in the package. Running this example would raise an ImportError.

The gt_i18n package exports I18nManager and set_i18n_manager for initialization, not an init_gt function. Framework-specific setup is handled by initialize_gt from gt-fastapi / gt-flask — there is no equivalent standalone init_gt in gt_i18n.

Suggested change

	from gt_i18n import t, init_gt
	init_gt(default_locale="en", locales=["en", "es", "fr"])
	print(t("Hello, world!"))
	```python
	from gt_i18n import I18nManager, set_i18n_manager, t
	manager = I18nManager(default_locale="en", locales=["en", "es", "fr"])
	set_i18n_manager(manager)
	print(t("Hello, world!"))

<details><summary>Prompt To Fix With AI</summary>

`````markdown
This is a comment left during a code review.
Path: packages/gt-i18n/README.md
Line: 29-33

Comment:
**`init_gt` does not exist in `gt_i18n`**

The Quick Start imports and calls `init_gt`, but this function is not exported from `gt_i18n` and does not exist anywhere in the package. Running this example would raise an `ImportError`.

The `gt_i18n` package exports `I18nManager` and `set_i18n_manager` for initialization, not an `init_gt` function. Framework-specific setup is handled by `initialize_gt` from `gt-fastapi` / `gt-flask` — there is no equivalent standalone `init_gt` in `gt_i18n`.

```suggestion
```python
from gt_i18n import I18nManager, set_i18n_manager, t

manager = I18nManager(default_locale="en", locales=["en", "es", "fr"])
set_i18n_manager(manager)

print(t("Hello, world!"))

How can I resolve this? If you propose a fix, please make it concise.