docs: Add AGENTS.md files for root and each module

[Copilot]

Adds AGENTS.md files to give AI agents (and new contributors) a fast, accurate map of the repo, inspired by the equivalents in Infomaniak/android-kMail and Infomaniak/android-SwissTransfer.

Files added

• AGENTS.md (root) — Repository overview, module dependency graph (STCore → STCommon/STNetwork/STDatabase), build/test/publish commands, buildTools convention plugins, release flow (./buildRelease, nmcpAggregation, Versions.mavenVersionName, Package.swift), semantic-commit/PR title regex, and cross-cutting Kotlin/KMP conventions.
• STCommon/AGENTS.md — Shared interfaces, models, exceptions, Matomo constants, utils. Highlights that it is the only module re-exported in the STCore XCFramework (appleExportedProjects), so its public surface = the iOS Swift surface.
• STNetwork/AGENTS.md — ApiClientProvider (Ktor + OkHttp/Darwin), v1/v2 repositories, typed exception mapping (UnauthorizedException, TooManyRequestException, UploadErrorsException, …), ApiUrlMatcher strictness, kotlinx.serialization conventions.
• STDatabase/AGENTS.md — Parallel Realm (legacy) + Room/KSP (new) stacks, controllers vs DAOs, RealmMigrations, committed schemas/, and the Realm concurrency reason CI splits testDebugUnitTest / iosSimulatorArm64Test instead of running allTests.
• STCore/AGENTS.md — SwissTransferInjection facade and lazy managers, loadUser(userId) lifecycle, mapper boundary, expect/actual pattern (EmailLanguageUtils.android.kt / .apple.kt), and rules for keeping iOS-visible types in STCommon.

Conventions captured

Each file follows the same structure: Summary → Tech Stack → Layout → Local Norms → Conventions → Commands → JIT Index (rg/find recipes) → Gotchas. Module files cross-link back to the root and to their siblings.

No source or build configuration was changed.

[Copilot]

Pull request overview

Adds AGENTS.md documentation at the repository root and per-module level to provide a structured “map” of the codebase (modules, conventions, commands, and common gotchas) for AI agents and new contributors.

Changes:

• Added a top-level AGENTS.md describing repo structure, build/test/publish flows, and cross-cutting conventions.
• Added module-specific AGENTS.md files for STCommon, STNetwork, STDatabase, and STCore documenting responsibilities, layouts, and local norms.
• Included “JIT index” command snippets (rg/find) to speed up navigation.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
AGENTS.md	Top-level repository overview, commands, conventions, release and CI guidance.
STCommon/AGENTS.md	Documents shared contracts/public surface expectations for Swift via XCFramework export.
STNetwork/AGENTS.md	Documents Ktor client setup, repositories, error mapping, and URL helper strictness.
STDatabase/AGENTS.md	Documents Realm+Room migration, controllers/DAOs, schemas/migrations, and test strategy.
STCore/AGENTS.md	Documents SwissTransferInjection facade wiring, managers, and KMP patterns.

Comments suppressed due to low confidence (1)

STCore/AGENTS.md:142

• This gotcha refers to loadUser(userId), but SwissTransferInjection doesn’t expose that method. Consider updating this to point to accountManager.loadUser(...) / logoutCurrentUser(...) (or whatever the intended public flow is) so the guidance matches the current API.

- The `userAgent` parameter on `SwissTransferInjection` is part of the public constructor signature — renaming or
  removing it is a breaking change for all consumers.
- Don't bypass `loadUser(userId)` to swap accounts; the realm / database providers depend on it for per-user
  isolation.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[FabianDevel]

Don't put the regex in static here, because it's not evolutive and defeat the purpose of the ./github repo