Add dry-run guard for AWS scaling actions

[Cool-fire]

This change wires a new --dry-run flag from the CLI into the scaler/service layer so scaling commands can validate configs and report the intended action without mutating AWS resources.

Why this is needed:

• the reported regression was in the EC2 scale-down path, where a dry run still proceeded to the autoscaling update call instead of only reporting the intended change
• the existing service layout made the smallest safe fix to pass dry-run intent through cmd/root.go -> pkg/scaler.go -> pkg/service/*

What changed:

• added --dry-run to the Cobra root command and passed it into pkg.ScaleApp
• threaded dryRun through the scaler dispatch so each AWS service can short-circuit before its mutation call
• updated the EC2 autoscaling service to log the intended scale-up/scale-down action and skip UpdateAutoScalingGroup during dry runs
• added the same dry-run no-op behavior for the other AWS service handlers so the CLI does not apply changes when --dry-run is set
• added a regression test covering EC2 scale-down dry runs and asserting they log the action while never calling the autoscaling client

Verification:

• attempted gofmt -w cmd/root.go pkg/scaler.go pkg/service/ec2.go pkg/service/elasticache.go pkg/service/kinesis.go pkg/service/dynamodb.go pkg/service/ec2_test.go -> failed because gofmt is not installed in this sandbox (/usr/bin/bash: line 1: gofmt: command not found)
• attempted go env GOROOT / which go to locate the toolchain -> failed because go is not installed in this sandbox
• tests could not be run here for the same reason

Limitations:

• I could not format or execute the Go test suite in this environment due the missing Go toolchain, so the PR notes that explicitly

Files changed

cmd/root.go                |  4 +++-
 pkg/scaler.go              | 18 ++++++++--------
 pkg/service/dynamodb.go    |  9 +++++++-
 pkg/service/ec2.go         | 19 +++++++++++++++--
 pkg/service/ec2_test.go    | 53 ++++++++++++++++++++++++++++++++++++++++++++++
 pkg/service/elasticache.go | 12 ++++++++++-
 pkg/service/kinesis.go     |  8 ++++++-
 7 files changed, 108 insertions(+), 15 deletions(-)

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