Standardized pipeline naming to devafusion-<domain>-<ci|cd>

The web and infrastructure pipeline pairs had drifted onto two different naming schemes - fixed the half of each pair that didn't match its sibling so every pipeline name, YAML file path, and cross-pipeline resource reference now follows the same devafusion-<domain>-<ci|cd> pattern.

Decisions

Standardize on the infrastructure/ domain name (matching the actual repository folder and its infrastructure/AGENTS.md spoke) rather than terraform, since terraform is the tool used inside that domain, not the domain itself.
Fix whichever half of each CI/CD pair didn't already match the target pattern, rather than picking a side arbitrarily: devafusion-web-ci and devafusion-infrastructure-cd were already correct, so devafusion-dev-cd and devafusion-terraform-ci were the ones renamed.
Leave the Azure App Service name, resource group name, and Azure DevOps environment name (devafusion-dev) untouched, since those identify Azure resources and an approval environment, not pipeline identity, and are outside this naming pass.

Milestones

Renamed pipelines/ci/terraform.yml to pipelines/ci/infrastructure.yml and updated its self-referencing trigger/pr path filters.
Renamed pipelines/cd/dev.yml to pipelines/cd/web.yml.
Updated pipelines/cd/infrastructure.yml's pipeline resource (name, source, download alias) and plan artifact path to match the renamed CI pipeline.
Updated AGENTS.md's Pre-Flight Gate path check and gitleaks CI reference to the renamed pipeline files and name.
Flagged the matching Azure DevOps portal renames (devafusion-terraform-ci to devafusion-infrastructure-ci, devafusion-dev-cd to devafusion-web-cd) as a manual follow-up, since registered pipeline definitions live outside this repository.

Validation

git diff --check
Reviewed both renamed and both untouched pipeline YAML files for every remaining cross-reference to the old file paths and pipeline names.