Address lintr findings (259 issues)

[NewGraphEnvironment]

Problem

lintr::lint_package() reports 259 issues across the codebase after migration.

Summary by Linter

#	Done	Linter	Count	Type
1	[ ]	line_length_linter	178	style - lines > 80 chars
2	[ ]	commented_code_linter	18	style - commented-out code
3	[ ]	object_usage_linter	16	potential bugs
4	[ ]	quotes_linter	10	style - quote consistency
5	[ ]	object_name_linter	8	style - naming conventions
6	[ ]	trailing_blank_lines_linter	8	style - extra blank lines
7	[ ]	indentation_linter	7	style - inconsistent indent
8	[ ]	return_linter	5	style - explicit returns
9	[ ]	brace_linter	3	style - brace placement
10	[ ]	commas_linter	2	style - spacing after commas
11	[ ]	paren_body_linter	2	style - space after parens
12	[ ]	semicolon_linter	2	style - trailing semicolons

object_usage_linter Details (#3 - Priority)

These 16 issues flag potential bugs or missing declarations:

NSE (Non-Standard Evaluation) false positives:

• spk_join.R:59,61 - .data pronoun (dplyr NSE)
• spk_join.R:86 - across, all_of (dplyr verbs)
• spk_layer_info.R:32,47 - name, driver columns
• spk_q_layer_info.R:67-68 - layer_name, time_exported, name
• spk_rast_rm_empty.R:30 - spk_rast_not_empty function reference

Unused local variables:

• spk_join.R:96 - changed_details assigned but not used
• spk_q_layer_info.R:51 - nodes assigned but not used
• spk_stac_calc.R:201 - id assigned but not used
• spk_stac_calc.R:240,250,258 - t0, t1, t2 timing vars

Proposed Solution

1. Configure .lintr to set line length to 120 chars (CLAUDE.md specifies 120)
2. Add globalVariables() for NSE column names (already partially done in utils.R)
3. Review unused variables - some are legitimate (timing vars used conditionally), others can be removed
4. Incrementally fix style issues in future commits

Configuration

Create .lintr file:

linters: linters_with_defaults(
  line_length_linter(120)
)