Update tool dependencies and fix new lint issues (#36702)

## Summary
- Update golangci-lint v2.9.0 → v2.10.1, misspell v0.7.0 → v0.8.0,
actionlint v1.7.10 → v1.7.11
- Fix 20 new QF1012 staticcheck findings by using `fmt.Fprintf` instead
of `WriteString(fmt.Sprintf(...))`
- Fix SA1019: replace deprecated `ecdsa.PublicKey` field access with
`PublicKey.Bytes()` for JWK encoding, with SEC 1 validation and curve
derived from signing algorithm
- Add unit test for `ToJWK()` covering P-256, P-384, and P-521 curves,
also verifying correct coordinate padding per RFC 7518
- Remove dead staticcheck linter exclusion for "argument x is
overwritten before first use"

## Test plan
- [x] `make lint-go` passes with 0 issues
- [x] `go test ./services/oauth2_provider/ -run
TestECDSASigningKeyToJWK` passes for all curves

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

services/webhook/slack.go

@@ -211,7 +211,7 @@ func (s slackConvertor) Push(p *api.PushPayload) (SlackPayload, error) {
 	var attachmentText strings.Builder
 	// for each commit, generate attachment text
 	for i, commit := range p.Commits {
-		attachmentText.WriteString(fmt.Sprintf("%s: %s - %s", SlackLinkFormatter(commit.URL, commit.ID[:7]), SlackShortTextFormatter(commit.Message), SlackTextFormatter(commit.Author.Name)))
+		fmt.Fprintf(&attachmentText, "%s: %s - %s", SlackLinkFormatter(commit.URL, commit.ID[:7]), SlackShortTextFormatter(commit.Message), SlackTextFormatter(commit.Author.Name))
 		// add linebreak to each commit but the last
 		if i < len(p.Commits)-1 {
 			attachmentText.WriteString("\n")