[docs] add design decision record process and template

docs/decisions/0000-template.md

@@ -0,0 +1,56 @@
+# NNNN. Title stating the decision as a fact
+
+<!-- Good: "Clicks scroll elements into view before interacting"
+     Bad:  "Click behavior" -->
+
+- Status: Proposed <!-- Proposed | Accepted | Rejected | Superseded by [NNNN](NNNN-title.md) -->
+- Date: YYYY-MM-DD <!-- date the status last changed -->
+- Discussion: <!-- link to this record's PR; add prior issues/threads under Context -->
+
+## Context
+
+What problem are we solving, and what forces are in tension? W3C spec language, user
+expectations, existing behavior that differs between bindings, implementation constraints.
+Link prior discussions (issues, TLC notes) here as background — but summarize them, since
+this section must make sense without following any links.
+
+## Decision
+
+The decision, stated in language-neutral terms. This is the normative part: what every
+binding MUST do, and what is explicitly left to per-language idiom. Use code sketches per
+language here if the API shape is part of what's being decided.
+
+## Considered options
+
+- **Option A** — what it is; why it was rejected or accepted
+- **Option B** — what it is; why it was rejected or accepted
+
+<!-- Options must be mutually exclusive answers to the question stated in Context; if two
+     options could both be adopted, they are separate decisions and the document should be
+     split. Revise this section during review as alternatives are contested or added — the
+     merged record, not the PR thread, is the authoritative account of why each rejected
+     option was not chosen. -->
+
+## Consequences
+
+What gets easier, what gets harder, what users will notice. Deprecations triggered by this
+decision and their timelines. Follow-up decisions this one makes necessary.
+
+## Binding status
+
+<!-- Update this table as bindings converge on the decision; table updates don't need
+     TLC review. "n/a" with a note if the decision doesn't apply to a binding. -->
+
+| Binding    | Status  | Notes / tracking link |
+|------------|---------|-----------------------|
+| Java       | pending |                       |
+| Python     | pending |                       |
+| Ruby       | pending |                       |
+| .NET       | pending |                       |
+| JavaScript | pending |                       |
+
+## Appendix (optional)
+
+Durable supporting material the decision relies on: benchmarks, spec excerpts, survey of
+behavior in other tools. Delete this section if there is none — ephemeral evidence belongs
+in the PR thread instead.

docs/decisions/README.md

@@ -0,0 +1,71 @@
+# Design Decisions
+
+This directory is the log of design decisions that apply across the Selenium project —
+one file per decision, numbered in the order they were proposed.
+
+Selenium ships the same API in multiple languages. Decisions about user-visible behavior,
+API shape, and cross-binding semantics need to be made once, recorded, and implemented
+consistently everywhere. This log is the canonical record of those decisions: when a
+question comes up in review, the answer should be a link to a file here.
+
+## What needs a decision record
+
+- User-visible behavior that should be consistent across bindings: API naming and shape,
+  error types and messages, default timeouts, capability handling
+- WebDriver Classic / BiDi semantics and how the protocol is exposed (or deliberately not exposed)
+- Deprecation and backwards-compatibility commitments
+- Anything the TLC has labeled [`A-needs-decision`](https://github.com/SeleniumHQ/selenium/labels/A-needs-decision)
+  and resolved
+
+## What doesn't
+
+- Single-binding internals (a Java maintainer picking a data structure)
+- Build tooling and infrastructure choices
+- Anything cheaply reversible
+
+When in doubt, ask whether the question is likely to be raised again. If it is, record the decision.
+
+## Process
+
+1. **Propose.** Anyone may propose: copy [0000-template.md](0000-template.md) to `NNNN-short-title.md` using the
+   next unused number, fill it in, and open a PR with `Status: Proposed`. Keep it to about a
+   page — if the debate already happened in an issue, the record can be short and link to it.
+2. **Discuss.** The PR thread is the discussion record. Decisions that need synchronous
+   discussion are raised at a TLC meeting; the outcome goes back into the PR. Disagreement
+   about the considered options is resolved by revising the document during review, so the
+   merged record reflects the debate accurately. The TLC sets its meeting agenda; proposals
+   advance as agenda time allows.
+3. **Decide.** The Selenium Project Lead merges the record once the approval requirements
+   below are met and discussion has run its course, with the status updated to `Accepted` —
+   merging constitutes acceptance. Proposals the TLC considers and declines are merged as
+   `Rejected`; proposals withdrawn or abandoned before TLC consideration are closed and the
+   number lapses.
+4. **Implement.** Each binding tracks its convergence in the decision's binding-status table.
+   Updating that table (and only that table) doesn't require TLC review.
+
+## Approval
+
+- TLC members respond to a proposal with a GitHub review: an approval, a "no objection"
+  comment review (saw it, deferring to the others), or a request-changes review stating
+  what would resolve it.
+- Records are accepted by consensus: a majority of TLC members have responded, none with
+  an unresolved objection. Before acceptance, a record must have been open at least one
+  week and an agenda item at a TLC meeting — no one should learn of a decision after it
+  is made.
+- If substantive edits are made, the author re-requests reviews.
+- An objection that revision cannot resolve — including support for a different considered
+  option — is discussed at a TLC meeting. If consensus still fails, the Selenium Project
+  Lead decides which position prevails; the record is updated to match, and overruled
+  dissent is summarized rather than erased.
+
+## Rules
+
+- **A decision must stand alone.** A reader gets the decision, the rationale, and the rejected
+  alternatives without following any links; linked material is background, not required reading.
+- **Accepted decisions are immutable**, except for the status line and the binding-status
+  table. Changing a decision means a new record that supersedes the old one — update the old
+  record's status to `Superseded by [NNNN](...)`.
+- **Numbers are stable once merged.** They get cited in reviews and issues. If two open PRs
+  claim the same number, the later one renames before merge. Gaps in numbering are acceptable.
+- **Durable supporting material goes in the record itself** (an Appendix section at the end).
+  Ephemeral evidence and debate stay in the PR thread.