Fix part of #6106: Add App and Feature Release Process wiki page (#6349)
Fixes part of #6106
## Explanation
Adds the **App and Feature Release Process** wiki page — the canonical,
coordinator-facing documentation for the oppia-android binary release
lifecycle and feature flag workflow.
This wiki replaces the previous private release Google Doc and serves as
the canonical, coordinator-facing documentation for the app and feature
release process.
### What the page covers
| Section | Content |
|---|---|
| §1 Prerequisites & Roles | Required GitHub environments, GCP
permissions, and Play Console access |
| §2 Binary Release Lifecycle | Nine subsections covering version
numbering, changelog generation, release branch creation, build & sign,
Firebase QA, Play Console deploy, staged rollout, post-release changelog
updates, and automated alpha releases |
| §3 Feature Flag Lifecycle | How feature flags are created, enabled
per-flavor, and retired |
| §4 Diagrams | Mermaid diagrams for the end-to-end release flow,
automated alpha flow, and feature flag lifecycle |
| §5 Workflow Quick-Access Table | Summary of every workflow file, its
trigger, and key inputs |
Each §2.x subsection documents the corresponding GitHub Actions workflow
(trigger, required inputs, what it does, and failure guidance) so
coordinators have a single reference rather than reading each `.yml`
file individually.
## Disclosure of LLM Usage
AI was used for writing and research.
## Essential Checklist
- [x] The PR title starts with "Fix #bugnum: " (If this PR fixes part of
an issue, prefix the title with "Fix part of #bugnum: ...".)
- [x] The explanation section above starts with "Fixes #bugnum: " (If
this PR fixes part of an issue, use instead: "Fixes part of #bugnum:
...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).