refactor(discovery): decompose the fingerprint god-file by role (WS-D)

[krisarmstrong]

Summary

Splits internal/discovery/fingerprint.go (786 LOC) into four role-based files in package discovery:

• fingerprint.go — core probing + port-scan orchestration
• osfp.go — OS fingerprinting (banner/HTTP/server matchers)
• service.go — service-version detection (SSH/FTP/SMTP/Telnet)
• tls.go — TLS probing + version stringification

Pure move — no behavior change, no API change. All new files are under the
600-line size-gate threshold; declaration sets and code-line multisets
verified identical to the original.

Linked Issue

Related to #187

Type of Change

• Chore / refactor / dependency update

Risk

• Low

Testing Evidence

Independently verified from a clean worktree of the branch (not the agent's word):

declaration-set diff:   ✅ IDENTICAL
code-line multiset diff: ✅ IDENTICAL
gofmt -l:               clean
go build:               OK
go vet:                 OK
go test -race:          ok
golangci-lint:          0 issues
check-filename-policy:  ✓
file-size gate:         all split files <600

Security and Release Checklist

• No secrets, tokens, credentials, or customer data are included.
• Mutating routes, auth surfaces, permission checks, and output encoding were reviewed if touched. (none — pure file split)
• Dependencies are pinned and justified if changed. (none changed)
• Documentation, screenshots, or operator notes were updated if behavior changed. (no behavior change)

[github-actions]

📋 License Compliance Report

✅ All dependencies pass license compliance checks

Go Dependencies

• Unknown: 118 package(s)
• MIT: 30 package(s)
• BSD-3-Clause: 17 package(s)
• Apache-2.0: 12 package(s)
• BSD-2-Clause: 2 package(s)

npm Dependencies

See full report in workflow artifacts

Allowed Licenses: MIT, Apache-2.0, BSD-*, ISC, CC0-1.0, MPL-2.0
Forbidden: GPL, AGPL, SSPL (strong copyleft)

[github-actions]

📋 License Compliance Report

✅ All dependencies pass license compliance checks

Go Dependencies

• Unknown: 118 package(s)
• MIT: 30 package(s)
• BSD-3-Clause: 17 package(s)
• Apache-2.0: 12 package(s)
• BSD-2-Clause: 2 package(s)

npm Dependencies

See full report in workflow artifacts

Allowed Licenses: MIT, Apache-2.0, BSD-*, ISC, CC0-1.0, MPL-2.0
Forbidden: GPL, AGPL, SSPL (strong copyleft)

[github-actions]

📋 License Compliance Report

✅ All dependencies pass license compliance checks

Go Dependencies

• Unknown: 118 package(s)
• MIT: 30 package(s)
• BSD-3-Clause: 17 package(s)
• Apache-2.0: 12 package(s)
• BSD-2-Clause: 2 package(s)

npm Dependencies

See full report in workflow artifacts

Allowed Licenses: MIT, Apache-2.0, BSD-*, ISC, CC0-1.0, MPL-2.0
Forbidden: GPL, AGPL, SSPL (strong copyleft)

[github-actions]

📋 License Compliance Report

✅ All dependencies pass license compliance checks

Go Dependencies

• Unknown: 118 package(s)
• MIT: 30 package(s)
• BSD-3-Clause: 17 package(s)
• Apache-2.0: 12 package(s)
• BSD-2-Clause: 2 package(s)

npm Dependencies

See full report in workflow artifacts

Allowed Licenses: MIT, Apache-2.0, BSD-*, ISC, CC0-1.0, MPL-2.0
Forbidden: GPL, AGPL, SSPL (strong copyleft)