refactor: eliminate three near-duplicate/outlier functions flagged by semantic analysis

[Copilot]

Three recurring code-quality findings from semantic function clustering analysis: a near-duplicate pair across server/proxy, a misplaced config validator, and a trivial one-liner wrapper.

Changes

• internal/httputil — add shared ParseRateLimitResetHeader(value string) time.Time with strings.TrimSpace normalization, replacing two near-identical private implementations:

  • parseRateLimitResetHeader in internal/server/circuit_breaker.go (had TrimSpace)
  • parseRateLimitReset in internal/proxy/handler.go (lacked TrimSpace)

• internal/config/validation.go — move validateGuardPolicies here from guard_policy.go; it takes *Config and belongs alongside validateGatewayConfig, validateTrustedBots, validateOpenTelemetryConfig, etc. Replace logGuardPolicy → logValidation.

• internal/proxy/graphql.go — remove truncateForLog (a one-line pass-through to strutil.TruncateRunes); inline strutil.TruncateRunes(s, 80) directly at the two call sites, consistent with the rest of the codebase.

Test changes

• Added TestParseRateLimitResetHeader to httputil_test.go (includes whitespace-trimming case).
• Removed TestParseRateLimitResetHeader from circuit_breaker_test.go and TestParseRateLimitReset from rate_limit_test.go — now covered by the shared test.
• Removed graphql_test.go (only contained TestTruncateForLog; strutil.TruncateRunes is already tested in strutil/truncate_test.go).

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• example.com
  • Triggering command: /tmp/go-build907643046/b514/launcher.test /tmp/go-build907643046/b514/launcher.test -test.testlogfile=/tmp/go-build907643046/b514/testlog.txt -test.paniconexit0 -test.timeout=10m0s .cfg�� 6809213/b405/_pk-errorsas 0L32/Gn657Kg8UZO-ifaceassert x_amd64/vet --gdwarf-5 /http2/hpack -o x_amd64/vet .cfg�� lete: awmg" ache/go/1.25.8/x64/src/crypto/tls/alert.go x_amd64/vet . --gdwarf2 --64 x_amd64/vet (dns block)
• invalid-host-that-does-not-exist-12345.com
  • Triggering command: /tmp/go-build907643046/b496/config.test /tmp/go-build907643046/b496/config.test -test.testlogfile=/tmp/go-build907643046/b496/testlog.txt -test.paniconexit0 -test.timeout=10m0s /tmp/go-build907643046/b395/vet.cfg /testutil/mcptesgo1.25.8 /testutil/mcptes-c=4 x_amd64/vet 6809213/b151/ -imultiarch x86_64-linux-gnu-bool x_amd64/vet 6809�� g_.a olang.org/grpc@v-ifaceassert 64/pkg/tool/linu-nilfunc . ce/tracetest --64 64/pkg/tool/linu-buildtags (dns block)
• nonexistent.local
  • Triggering command: /tmp/go-build907643046/b514/launcher.test /tmp/go-build907643046/b514/launcher.test -test.testlogfile=/tmp/go-build907643046/b514/testlog.txt -test.paniconexit0 -test.timeout=10m0s .cfg�� 6809213/b405/_pk-errorsas 0L32/Gn657Kg8UZO-ifaceassert x_amd64/vet --gdwarf-5 /http2/hpack -o x_amd64/vet .cfg�� lete: awmg" ache/go/1.25.8/x64/src/crypto/tls/alert.go x_amd64/vet . --gdwarf2 --64 x_amd64/vet (dns block)
• slow.example.com
  • Triggering command: /tmp/go-build907643046/b514/launcher.test /tmp/go-build907643046/b514/launcher.test -test.testlogfile=/tmp/go-build907643046/b514/testlog.txt -test.paniconexit0 -test.timeout=10m0s .cfg�� 6809213/b405/_pk-errorsas 0L32/Gn657Kg8UZO-ifaceassert x_amd64/vet --gdwarf-5 /http2/hpack -o x_amd64/vet .cfg�� lete: awmg" ache/go/1.25.8/x64/src/crypto/tls/alert.go x_amd64/vet . --gdwarf2 --64 x_amd64/vet (dns block)
• this-host-does-not-exist-12345.com
  • Triggering command: /tmp/go-build907643046/b523/mcp.test /tmp/go-build907643046/b523/mcp.test -test.testlogfile=/tmp/go-build907643046/b523/testlog.txt -test.paniconexit0 -test.timeout=10m0s .cfg�� FM1m/LEd7bURSK2u2w4dcFM1m /tmp/go-build1626809213/b288/ x_amd64/vet � Warning: golanrunc --gdwarf2 --64 x_amd64/vet .cfg�� 6184859/b100/vet.cfg -trimpath x_amd64/vet lock.go lock_sort.go -lang=go1.19 x_amd64/vet (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[Copilot]

Pull request overview

Refactors a few small utilities to reduce duplication and keep validation/helpers in more appropriate packages, based on semantic analysis findings.

Changes:

• Added internal/httputil.ParseRateLimitResetHeader and updated proxy rate-limit handling to use it.
• Moved validateGuardPolicies into internal/config/validation.go to align with other config validation helpers.
• Inlined strutil.TruncateRunes(..., 80) at GraphQL logging call sites and removed the now-redundant wrapper + its dedicated test file.

Show a summary per file

File	Description
internal/server/circuit_breaker_test.go	Removes the server-local header parsing test now covered by shared httputil tests.
internal/server/circuit_breaker.go	Deletes an unused/duplicated parseRateLimitResetHeader helper.
internal/proxy/rate_limit_test.go	Removes proxy-local header parsing test now covered by shared httputil tests.
internal/proxy/handler.go	Switches rate-limit reset parsing to httputil.ParseRateLimitResetHeader.
internal/proxy/graphql_test.go	Removes a test file that only exercised a trivial wrapper.
internal/proxy/graphql.go	Inlines strutil.TruncateRunes and removes truncateForLog.
internal/httputil/httputil_test.go	Adds shared tests for the new reset-header parsing helper (including whitespace trimming).
internal/httputil/httputil.go	Introduces shared ParseRateLimitResetHeader helper.
internal/config/validation.go	Adds validateGuardPolicies alongside other config validation routines.
internal/config/guard_policy.go	Removes validateGuardPolicies from guard policy implementation file.

Copilot's findings

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• Files reviewed: 10/10 changed files
• Comments generated: 0