Add Interop 2025 proposal templates (#680)

* Restore proposal templates from Interop 2024

These are the 2024 templates without changes.

* Update dates in proposal templates

October 3 is from #657.

* Align specification requirements with 2024 process

Expanded to match https://github.com/web-platform-tests/interop/blob/main/2024/selection-process.md#open-call-for-focus-area-and-investigation-proposals

* Update focus-area-proposal.yml

Author: foolip

.github/ISSUE_TEMPLATE/focus-area-proposal.yml

@@ -0,0 +1,53 @@
+name: Focus Area Proposal
+description: Proposal for an Interop 2025 Focus Area
+labels: focus-area-proposal
+body:
+- type: markdown
+  attributes:
+    value: |
+      Thanks for taking the time to make a proposal for Interop 2025!
+
+      Be sure to read the [proposal guide](https://github.com/web-platform-tests/interop/blob/main/proposal_guide.md) to give your proposal the best chance of success!
+
+      Note: If this feature is widely implemented, but lacks a high quality specification or tests, an [Investigation Effort](https://github.com/web-platform-tests/interop/issues/new?template=investigation-effort-proposal.yml) may be more appropriate.
+
+      When you submit your proposal, a GitHub issue will be created to track it. Please check back on GitHub from time to time to answer any questions we have. You'll also be able to make changes to your proposal from now until October 3 by commenting on your issue. See our [README](https://github.com/web-platform-tests/interop/blob/main/2025/README.md) for the full timeline of Interop 2025.
+- type: markdown
+  attributes:
+    value: "## Proposal Details"
+- type: textarea
+  attributes:
+    label: Description
+    description: Brief description of the feature. Try to be clear about what parts of the feature are included and not.
+  validations:
+    required: true
+- type: input
+  attributes:
+    label: Specification
+    description: |
+      Specification for the feature. The feature must defined by a standards-track specification from one of the following organizations:
+
+      - [Alliance for Open Media](https://aomedia.org/)
+      - [IETF](https://www.ietf.org/) (Standard Track)
+      - [ISO](https://www.iso.org/)
+      - [Khronos Group](https://www.khronos.org/)
+      - [TC39](https://tc39.es/) (Stage 2+)
+      - [W3C](https://www.w3.org/) (Recommendation Track)
+      - [WebAssembly](https://webassembly.org/specs/) (Phase 3+)
+      - [WHATWG](https://whatwg.org/)
+  validations:
+    required: true
+- type: textarea
+  attributes:
+    label: Additional Signals
+    description: |
+      Any additional signals from our [proposal guide](https://github.com/web-platform-tests/interop/blob/main/proposal_guide.md):
+
+      - Standards Positions
+      - Site Breakage and Workaround
+      - Size and Current State of the Feature
+      - Browser Bugs
+      - Developer Surveys
+      - Other Developer Sentiment
+      - Likely Compatibility Impact
+      - Platform Impact

.github/ISSUE_TEMPLATE/investigation-effort-proposal.yml

@@ -0,0 +1,33 @@
+name: Investigation Effort Proposal
+description: Proposal for an Interop 2025 Investigation Effort
+labels: investigation-effort-proposal
+body:
+- type: markdown
+  attributes:
+    value: |
+      Thanks for taking the time to make a proposal for Interop 2025!
+
+      This form is for features that are widely implemented, but lack high quality specifications or tests. If this feature does have a high quality specification and tests, please file a [Focus Area](https://github.com/web-platform-tests/interop/issues/new?template=focus-area-proposal.yml) proposal instead. If you're not sure which kind of proposal to submit, pick one and we will help you out.
+
+      When you submit your proposal, a GitHub issue will be created to track it. Please check back on GitHub from time to time to answer any questions we have. You'll also be able to make changes to your proposal from now until October 3 by commenting on your issue. See our [README](https://github.com/web-platform-tests/interop/blob/main/2025/README.md) for the full timeline of Interop 2025.
+- type: textarea
+  attributes:
+    label: Description
+    description: Brief description of the feature. Try to be clear about what parts of the feature are included and not.
+- type: textarea
+  attributes:
+    label: Rationale
+    description: |
+      Reasons for including the feature. A few dimensions to consider are:
+
+      - Web developer sentiment from polls or surveys, for example, [MDN surveys](https://insights.developer.mozilla.org/) or [State of CSS](https://stateofcss.com/).
+      - Examples of sites or libraries working around a missing feature or browser bug.
+      - Browser bugs or browser bug statistics, for example, [Chromium](https://bugs.chromium.org/), [Gecko](https://bugzilla.mozilla.org/),  or [WebKit](https://bugs.webkit.org/).
+      - Current usage of the feature, for example, [Chrome use counters](https://www.chromestatus.com/metrics/feature/popularity) or [HTTP Archive](https://httparchive.org/).
+- type: textarea
+  attributes:
+    label: Investigation Roadmap
+    description: |
+      Please describe the steps necessary to get this feature to a state of high quality specification and tests. Link to existing spec and tests, and describe what needs to be done, ideally as a set of distinct tasks. If there are open-ended questions about the behavior that require investigation, try to still capture this as a set of tasks, such as "test existing behavior", "update specification", and "update tests".
+
+      Any standards work must be done in the appropriate standards group, and those doing the work need to join that group. Interop 2025 is not a venue for specifying new features.