[net] move slaac module from utils to net

[abtink]

This commit moves the SlaacAddress module from src/core/utils to src/core/net.

This change also updates the namespace from ot::Utils to ot::Ip6 and updates all includes and usages throughout the codebase.

The SlaacAddress module was originally placed in core/utils as SLAAC management was historically handled by the platform. Now that the OpenThread stack manages SLAAC directly, this logic is better placed under core/net.

[github-actions]

Merging #11955 into main

name	branch	text	data	bss	total
ot-cli-ftd	466fdb8	479704	860	66580	547144
	d4ae270	479688	860	66580	547128
	+/-	-16	+0	+0	-16
ot-ncp-ftd	466fdb8	446236	764	61824	508824
	d4ae270	446236	764	61824	508824
	+/-	+0	+0	+0	+0
ot-cli-mtd	466fdb8	372432	764	51052	424248
	d4ae270	372432	764	51052	424248
	+/-	+0	+0	+0	+0
ot-ncp-mtd	466fdb8	353580	764	46320	400664
	d4ae270	353580	764	46320	400664
	+/-	+0	+0	+0	+0
ot-cli-ftd-br	466fdb8	582080	868	136404	719352
	d4ae270	582080	868	136404	719352
	+/-	+0	+0	+0	+0
ot-rcp	466fdb8	63136	568	20804	84508
	d4ae270	63136	568	20804	84508
	+/-	+0	+0	+0	+0

Library files

name	branch	text	data	bss	total
libopenthread-ftd.a	466fdb8	246914	95	40358	287367
	d4ae270	246914	95	40358	287367
	+/-	+0	+0	+0	+0
libopenthread-cli-ftd.a	466fdb8	60843	0	8083	68926
	d4ae270	60843	0	8083	68926
	+/-	+0	+0	+0	+0
libopenthread-ncp-ftd.a	466fdb8	33561	0	5948	39509
	d4ae270	33561	0	5948	39509
	+/-	+0	+0	+0	+0
libopenthread-mtd.a	466fdb8	165279	0	24854	190133
	d4ae270	165279	0	24854	190133
	+/-	+0	+0	+0	+0
libopenthread-cli-mtd.a	466fdb8	41134	0	8059	49193
	d4ae270	41134	0	8059	49193
	+/-	+0	+0	+0	+0
libopenthread-ncp-mtd.a	466fdb8	25805	0	5948	31753
	d4ae270	25805	0	5948	31753
	+/-	+0	+0	+0	+0
libopenthread-ftd-br.a	466fdb8	350843	100	110150	461093
	d4ae270	350843	100	110150	461093
	+/-	+0	+0	+0	+0
libopenthread-cli-ftd-br.a	466fdb8	78523	0	8115	86638
	d4ae270	78523	0	8115	86638
	+/-	+0	+0	+0	+0
libopenthread-rcp.a	466fdb8	9944	0	5060	15004
	d4ae270	9944	0	5060	15004
	+/-	+0	+0	+0	+0
libopenthread-radio.a	466fdb8	19407	0	238	19645
	d4ae270	19407	0	238	19645
	+/-	+0	+0	+0	+0

[abtink]

/gemini review

[gemini-code-assist]

Code Review

This pull request correctly moves the SlaacAddress module from src/core/utils to src/core/net, which is a more logical location for this functionality given its direct relation to networking. The namespace is also appropriately updated from ot::Utils to ot::Ip6. All changes, including updates to build files and usages throughout the codebase, have been applied consistently. The refactoring is clean and well-executed, and I have no further comments.

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.78%. Comparing base (466fdb8) to head (6146922).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/core/api/ip6_api.cpp	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #11955      +/-   ##
==========================================
- Coverage   75.37%   73.78%   -1.59%     
==========================================
  Files         653      656       +3     
  Lines       93494   104026   +10532     
==========================================
+ Hits        70467    76759    +6292     
- Misses      23027    27267    +4240     

Files with missing lines	Coverage Δ
src/core/common/notifier.cpp	92.30% <100.00%> (+0.50%)	⬆️
src/core/common/settings.hpp	98.19% <ø> (+0.06%)	⬆️
src/core/instance/instance.hpp	65.36% <100.00%> (+31.64%)	⬆️
src/core/net/ip6.hpp	69.56% <ø> (ø)
src/core/net/slaac_address.cpp	77.77% <100.00%> (ø)
src/core/net/slaac_address.hpp	81.25% <ø> (ø)
src/core/thread/dua_manager.cpp	70.35% <100.00%> (-10.53%)	⬇️
src/core/thread/network_data_leader.cpp	92.28% <100.00%> (-2.79%)	⬇️
src/core/api/ip6_api.cpp	74.28% <0.00%> (+9.52%)	⬆️

... and 292 files with indirect coverage changes

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[Copilot]

Pull Request Overview

This PR moves the SlaacAddress module from src/core/utils to src/core/net to better reflect its purpose within the OpenThread stack's network layer, updating the namespace from ot::Utils to ot::Ip6.

• Updates namespace from ot::Utils::Slaac to ot::Ip6::Slaac throughout codebase
• Moves SLAAC module files from utils directory to net directory
• Updates all include statements and references to use the new location and namespace

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/core/thread/network_data_leader.cpp	Updates namespace reference from Utils::Slaac to Ip6::Slaac
src/core/thread/dua_manager.cpp	Updates namespace reference from Utils::Slaac to Ip6::Slaac
src/core/net/slaac_address.hpp	Changes namespace from Utils to Ip6, removes Ip6:: prefixes from types now in same namespace
src/core/net/slaac_address.cpp	Changes namespace from Utils to Ip6, removes Ip6:: prefixes for local types
src/core/net/ip6.hpp	Adds core-ip6-slaac to documentation groups
src/core/instance/instance.hpp	Updates include path and type references for moved SLAAC module
src/core/common/settings.hpp	Updates include path and type reference for SLAAC secret key
src/core/common/notifier.cpp	Updates namespace reference from Utils::Slaac to Ip6::Slaac
src/core/api/ip6_api.cpp	Updates namespace references from Utils::Slaac to Ip6::Slaac
src/core/CMakeLists.txt	Moves slaac_address.cpp from utils to net directory in build
src/core/BUILD.gn	Moves slaac_address source files from utils to net directory

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