Add architecture documentation.

[whisper67265]

Summary by CodeRabbit

• Documentation
  • Rewrote project README to use generalized placeholders and expanded workflow guidance for three workflows (triggers, payload fields, step-by-step actions, assets, required secrets, and configurable environment variables)
  • Added a comprehensive Architecture document describing goals, system context with flow diagrams, repository layout, branch model, control/data flows, cross-cutting concerns, non-goals, and stability/configuration notes

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR updates documentation: rewrites README.md to replace org-specific references with placeholders and expands workflow documentation for add-submodules, start-translation, and sync-translation (triggers, payloads, steps, assets, secrets, and repo vars). It also adds a new docs/ARCHITECTURE.md describing goals, system context, repository layout, branch model, control/data flows, cross-cutting concerns, and document stability.

Changes

Documentation Enhancement (single DAG)

Layer / File(s)	Summary
Architecture Foundation docs/ARCHITECTURE.md	New architecture document added: problem/goals, system context with Mermaid flowchart, repository codemap, branch model, control & data flows, cross-cutting concerns (auth, idempotency, safety, observability), and stability guidance.
README: High-level framing README.md	Replaced org-specific references with placeholders (e.g., MODULE_ORG, LANG_CODES) and linked architecture guidance.
README: Workflow Definitions README.md	Expanded three workflow sections (add-submodules, start-translation, sync-translation) with explicit triggers, JSON payload fields, per-workflow step sequences, and handling notes.
README: Assets & Distribution README.md	Documented workflow assets, snippet and asset files, and mirror/tag distribution behavior.
README: Secrets & Repo Variables README.md	Clarified required secrets (SYNC_TOKEN, WEBLATE_URL, WEBLATE_TOKEN) and repository variables (LANG_CODES, SUBMODULES_ORG) and their usage in workflows and scripts.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~15 minutes

"I hopped through lines with eager cheer,
Docs polished bright and placeholders near,
Workflows tidy, architecture penned,
A rabbit's wink—another PR to mend! 🐇✨"

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Add architecture documentation.' directly and clearly describes the primary change—the introduction of a new Architecture document (docs/ARCHITECTURE.md) with comprehensive workflow details.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[jonathanMLDev]

there are some link errors

[coderabbitai]

♻️ Duplicate comments (1)

README.md (1)

149-149: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Replace concrete org example with a neutral placeholder.

Line 149 still uses CppDigest as an example; using a placeholder (for example, {MODULE_ORG}) keeps the docs fully org-agnostic.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@README.md` at line 149, Update the README line referencing the SUBMODULES_ORG
example to use a neutral placeholder instead of the concrete "CppDigest" org:
replace the `CppDigest` example in the table cell for `SUBMODULES_ORG` (which
also mentions `sync-translation` and `.gitmodules`) with a placeholder like
`{MODULE_ORG}` so the docs remain org-agnostic and consistent with references to
`.gitmodules` URLs and the `sync-translation` behavior.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Duplicate comments:
In `@README.md`:
- Line 149: Update the README line referencing the SUBMODULES_ORG example to use
a neutral placeholder instead of the concrete "CppDigest" org: replace the
`CppDigest` example in the table cell for `SUBMODULES_ORG` (which also mentions
`sync-translation` and `.gitmodules`) with a placeholder like `{MODULE_ORG}` so
the docs remain org-agnostic and consistent with references to `.gitmodules`
URLs and the `sync-translation` behavior.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 4176c592-3e18-4126-b826-c87672041ba4

📥 Commits

Reviewing files that changed from the base of the PR and between 64e2fcf and 25867fd.

📒 Files selected for processing (2)

• README.md
• docs/ARCHITECTURE.md